diff --git a/.gitignore b/.gitignore
index 901d4e9..122341f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 .strideterm/
+api/config.local.php
diff --git a/README.md b/README.md
index 657b23d..9971cee 100644
--- a/README.md
+++ b/README.md
@@ -42,24 +42,36 @@ portfolio/
 
 File Station에서 두 폴더의 권한을 `http` 그룹에 쓰기 가능하게 설정하세요.
 
-### 4. 비밀번호 설정 (⚠️ 매우 중요)
+### 4. 관리자 비밀번호와 보안 설정
 
-**(A) 해시 생성**
-브라우저에서 접속:
+실제 관리자 비밀번호 해시는 저장소에 커밋하지 않습니다. 운영 서버에서는 다음 둘 중 하나로 설정하세요.
+
+**(A) api/config.local.php 사용 권장**
+
+1. `api/config.local.example.php`를 `api/config.local.php`로 복사합니다.
+2. 브라우저에서 다음 주소에 접속해 원하는 비밀번호의 해시를 생성합니다.
 ```
 http://your-nas/portfolio/generate_password.php
 ```
-원하는 비밀번호를 입력하면 해시가 출력됩니다.
+3. 생성된 해시를 `api/config.local.php`의 `ADMIN_PASSWORD_HASH` 값으로 넣습니다.
+4. `api/config.local.php`는 `.gitignore`에 포함되어 있으므로 저장소에 올리지 않습니다.
 
-**(B) config.php 수정**
-`api/config.php` 파일을 열어 아래 줄을 찾고:
-```php
-define('ADMIN_PASSWORD_HASH', '$2y$10$YourHashWillGoHere...');
+**(B) 환경변수 사용**
+
+서버 환경변수 `ADMIN_PASSWORD_HASH`에 `password_hash()`로 만든 해시를 설정해도 됩니다.
+
+```bash
+ADMIN_PASSWORD_HASH='$2y$10$replace_with_your_generated_hash'
 ```
-방금 생성된 해시로 교체합니다.
 
-**(C) generate_password.php 삭제**
-보안을 위해 반드시 삭제하세요!
+`api/config.php`에는 기본 관리자 비밀번호나 실제 해시가 들어 있지 않아야 합니다. 설정이 없으면 관리자 로그인은 실패합니다.
+
+**추가 운영 보안**
+
+- 로그인 후 상태 변경 API는 CSRF 토큰을 요구합니다. 프론트엔드의 `fetch` 흐름은 로그인/세션 확인 응답에서 받은 토큰을 자동으로 보냅니다.
+- 업로드 실패 응답에는 서버 내부 경로, 임시 경로, 저장 대상 경로가 노출되지 않습니다. 상세 오류는 서버 로그에서만 확인합니다.
+- URL 입력은 `http`, `https`, `uploads/` 상대 경로만 허용합니다. CSS 색상 값은 hex 색상 allowlist로 제한합니다.
+- 보안을 위해 `generate_password.php`는 설정 완료 후 운영 서버에서 삭제하거나 접근을 차단하세요.
 
 ### 5. 접속
 - 메인: `http://your-nas/portfolio/`
@@ -82,7 +94,8 @@ define('ADMIN_PASSWORD_HASH', '$2y$10$YourHashWillGoHere...');
 ## 🔒 보안 체크리스트
 
 - [ ] `generate_password.php` 삭제했는가?
-- [ ] `config.php`의 ADMIN_PASSWORD_HASH를 실제 해시로 교체했는가?
+- [ ] `api/config.local.php` 또는 `ADMIN_PASSWORD_HASH` 환경변수에 실제 관리자 해시가 설정되어 있는가?
+- [ ] `api/config.local.php`가 저장소에 커밋되지 않는가?
 - [ ] HTTPS 설정 (NAS의 Reverse Proxy 또는 Let's Encrypt)
 - [ ] 비밀번호는 8자 이상, 영문/숫자/기호 조합
 - [ ] `data/`, `uploads/` 폴더의 .htaccess 파일이 동작하는지 확인
@@ -107,7 +120,7 @@ git push -u origin main
 → `data/` 폴더의 쓰기 권한을 확인하세요.
 
 **로그인이 안 됨**
-→ `config.php`의 ADMIN_PASSWORD_HASH가 올바르게 교체되었는지 확인하세요.
+→ `api/config.local.php` 또는 `ADMIN_PASSWORD_HASH` 환경변수에 올바른 해시가 설정되어 있는지 확인하세요.
 
 **.htaccess가 동작하지 않음**
 → Web Station에서 Apache 사용 + `mod_rewrite`, `AllowOverride All` 설정 필요.
diff --git a/api/auth.php b/api/auth.php
index 5e0634a..9c47fe6 100644
--- a/api/auth.php
+++ b/api/auth.php
@@ -1,7 +1,7 @@
 <?php
 require_once 'config.php';
 require_once __DIR__ . '/error_config.php';
-session_start();
+start_secure_session();
 set_json_headers();
 
 $method = $_SERVER['REQUEST_METHOD'];
@@ -21,12 +21,16 @@ if ($method === 'POST' && $action === 'login') {
     // 무차별 대입 방지 - 간단한 딜레이
     usleep(500000); // 0.5초
     
+    if (ADMIN_PASSWORD_HASH === '') {
+        json_response(['error' => 'Admin password is not configured'], 500);
+    }
+
     if (password_verify($password, ADMIN_PASSWORD_HASH)) {
         // 세션 고정 공격 방지
         session_regenerate_id(true);
         $_SESSION['authenticated'] = true;
         $_SESSION['login_time'] = time();
-        json_response(['success' => true, 'message' => '로그인 성공']);
+        json_response(['success' => true, 'message' => '로그인 성공', 'csrf_token' => ensure_csrf_token()]);
     } else {
         json_response(['error' => '비밀번호가 일치하지 않습니다'], 401);
     }
@@ -36,6 +40,8 @@ if ($method === 'POST' && $action === 'login') {
 // 로그아웃
 // =====================================================
 if ($method === 'POST' && $action === 'logout') {
+    require_auth();
+    require_csrf();
     session_destroy();
     json_response(['success' => true]);
 }
@@ -54,7 +60,11 @@ if ($method === 'GET' && $action === 'check') {
         }
     }
     
-    json_response(['authenticated' => $authenticated]);
+    $response = ['authenticated' => $authenticated];
+    if ($authenticated) {
+        $response['csrf_token'] = ensure_csrf_token();
+    }
+    json_response($response);
 }
 
 json_response(['error' => 'Invalid action'], 400);
diff --git a/api/categories.php b/api/categories.php
index a6cf8e4..83e9916 100644
--- a/api/categories.php
+++ b/api/categories.php
@@ -1,7 +1,7 @@
 <?php
 require_once 'config.php';
 require_once __DIR__ . '/error_config.php';
-session_start();
+start_secure_session();
 set_json_headers();
 
 define('CATEGORIES_FILE', DATA_DIR . '/categories.json');
@@ -12,7 +12,7 @@ $method = $_SERVER['REQUEST_METHOD'];
 function normalize_category($cat) {
     if (!isset($cat['parent_id'])) $cat['parent_id'] = null;
     if (!isset($cat['order'])) $cat['order'] = 0;
-    if (!isset($cat['color'])) $cat['color'] = '#00f2ff';
+    $cat['color'] = clean_css_color($cat['color'] ?? '#00f2ff');
     return $cat;
 }
 
@@ -35,6 +35,7 @@ if ($method === 'GET') {
 }
 
 require_auth();
+require_csrf();
 
 // =====================================================
 // POST: 카테고리 추가
@@ -42,7 +43,7 @@ require_auth();
 if ($method === 'POST') {
     $input = get_json_input();
     $name = trim($input['name'] ?? '');
-    $color = trim($input['color'] ?? '#00f2ff');
+    $color = clean_css_color($input['color'] ?? '#00f2ff');
     $parentId = isset($input['parent_id']) && $input['parent_id'] !== '' && $input['parent_id'] !== null
         ? intval($input['parent_id']) 
         : null;
@@ -115,7 +116,7 @@ if ($method === 'PUT') {
     foreach ($categories as $key => $cat) {
         if ($cat['id'] === $id) {
             if (isset($input['name'])) $categories[$key]['name'] = trim($input['name']);
-            if (isset($input['color'])) $categories[$key]['color'] = trim($input['color']);
+            if (isset($input['color'])) $categories[$key]['color'] = clean_css_color($input['color']);
             if (isset($input['order'])) $categories[$key]['order'] = intval($input['order']);
             // parent_id 변경은 허용하되, 자식이 있는 경우 자식으로 만들지 못하게
             if (array_key_exists('parent_id', $input)) {
diff --git a/api/config.local.example.php b/api/config.local.example.php
new file mode 100644
index 0000000..0b6b121
--- /dev/null
+++ b/api/config.local.example.php
@@ -0,0 +1,5 @@
+<?php
+// Copy this file to api/config.local.php on the server and replace the value.
+// Generate a hash with generate_password.php or:
+// php -r "echo password_hash('your-strong-password', PASSWORD_DEFAULT);"
+define('ADMIN_PASSWORD_HASH', '$2y$10$replace_with_your_generated_hash');
diff --git a/api/config.php b/api/config.php
index 2d20ffb..35bde31 100644
--- a/api/config.php
+++ b/api/config.php
@@ -1,39 +1,57 @@
 <?php
 // =====================================================
-// 설정 파일
+// Runtime configuration
 // =====================================================
-// ⚠️ 중요: 처음 사용 시 아래 ADMIN_PASSWORD_HASH를 변경하세요
-// 비밀번호 해시 생성 방법:
-//   브라우저에서 generate_password.php 접속 후 원하는 비번 입력
-//   또는 터미널에서: php -r "echo password_hash('your_password', PASSWORD_DEFAULT);"
+// ADMIN_PASSWORD_HASH is loaded from api/config.local.php or the environment.
+// Do not commit real password hashes or other secrets to the repository.
 // =====================================================
 
-// 기본 비밀번호: "admin1234" (반드시 변경하세요!)
-define('ADMIN_PASSWORD_HASH', '$2y$10$Wj/5fxQX90AlvyVPBfE0te2aUbysSBlE/Umm7EluG880rqcRUlHGm');
+$localConfig = __DIR__ . '/config.local.php';
+if (is_file($localConfig)) {
+    require_once $localConfig;
+}
 
-// 데이터 파일 경로
+if (!defined('ADMIN_PASSWORD_HASH')) {
+    $adminPasswordHash = getenv('ADMIN_PASSWORD_HASH');
+    define('ADMIN_PASSWORD_HASH', is_string($adminPasswordHash) ? trim($adminPasswordHash) : '');
+}
+
+// Data paths
 define('DATA_DIR', __DIR__ . '/../data');
 define('UPLOADS_DIR', __DIR__ . '/../uploads');
 define('PROJECTS_FILE', DATA_DIR . '/projects.json');
 define('PROFILE_FILE', DATA_DIR . '/profile.json');
 
-// 세션 설정
-define('SESSION_LIFETIME', 3600 * 4); // 4시간
+// Session settings
+define('SESSION_LIFETIME', 3600 * 4);
+
+function start_secure_session() {
+    if (session_status() !== PHP_SESSION_NONE) {
+        return;
+    }
+
+    session_set_cookie_params([
+        'lifetime' => 0,
+        'path' => '/',
+        'secure' => !empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off',
+        'httponly' => true,
+        'samesite' => 'Lax',
+    ]);
+    session_start();
+}
 
-// CORS 및 JSON 헤더
 function set_json_headers() {
     header('Content-Type: application/json; charset=utf-8');
     header('X-Content-Type-Options: nosniff');
 }
 
-// JSON 파일을 락 걸고 읽기
 function read_json_safe($filepath) {
     if (!file_exists($filepath)) {
         return null;
     }
     $fp = fopen($filepath, 'r');
     if (!$fp) return null;
-    
+
     if (flock($fp, LOCK_SH)) {
         $content = stream_get_contents($fp);
         flock($fp, LOCK_UN);
@@ -44,41 +62,33 @@ function read_json_safe($filepath) {
     return null;
 }
 
-// JSON 파일을 락 걸고 쓰기
+// Write JSON atomically so a crash during write does not leave a 0-byte file.
 function write_json_safe($filepath, $data) {
     $json = json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
     if ($json === false) return false;
-    
-    $fp = fopen($filepath, 'c+');
-    if (!$fp) return false;
-    
-    if (flock($fp, LOCK_EX)) {
-        ftruncate($fp, 0);
-        rewind($fp);
-        fwrite($fp, $json);
-        fflush($fp);
-        flock($fp, LOCK_UN);
-        fclose($fp);
-        return true;
+
+    $tmp = $filepath . '.tmp.' . uniqid('', true);
+    if (file_put_contents($tmp, $json, LOCK_EX) === false) {
+        @unlink($tmp);
+        return false;
     }
-    fclose($fp);
-    return false;
+    if (!rename($tmp, $filepath)) {
+        @unlink($tmp);
+        return false;
+    }
+    return true;
 }
 
-// 인증 체크
 function require_auth() {
-    if (session_status() === PHP_SESSION_NONE) {
-        session_start();
-    }
-    
+    start_secure_session();
+
     if (!isset($_SESSION['authenticated']) || $_SESSION['authenticated'] !== true) {
         http_response_code(401);
         echo json_encode(['error' => 'Unauthorized']);
         exit;
     }
-    
-    // 세션 타임아웃 체크
-    if (isset($_SESSION['login_time']) && 
+
+    if (isset($_SESSION['login_time']) &&
         (time() - $_SESSION['login_time']) > SESSION_LIFETIME) {
         session_destroy();
         http_response_code(401);
@@ -87,13 +97,67 @@ function require_auth() {
     }
 }
 
-// JSON 입력 받기
+function ensure_csrf_token() {
+    start_secure_session();
+    if (empty($_SESSION['csrf_token']) || !is_string($_SESSION['csrf_token'])) {
+        $_SESSION['csrf_token'] = bin2hex(random_bytes(32));
+    }
+    return $_SESSION['csrf_token'];
+}
+
+function require_csrf() {
+    start_secure_session();
+    $sessionToken = $_SESSION['csrf_token'] ?? '';
+    $requestToken = $_SERVER['HTTP_X_CSRF_TOKEN'] ?? '';
+
+    if (!is_string($sessionToken) || $sessionToken === '' ||
+        !is_string($requestToken) || !hash_equals($sessionToken, $requestToken)) {
+        json_response(['error' => 'Invalid CSRF token'], 403);
+    }
+}
+
 function get_json_input() {
     $input = file_get_contents('php://input');
     return json_decode($input, true);
 }
 
-// 응답 헬퍼
+function is_safe_public_url($url) {
+    if (!is_string($url)) return false;
+    $url = trim($url);
+    if ($url === '') return true;
+
+    if (preg_match('#^uploads/[A-Za-z0-9가-힣._~!$&\'()*+,;=:@%/-]+$#u', $url)) {
+        return !str_contains($url, '..') && !preg_match('#(^|/)\.#', $url);
+    }
+
+    $parts = parse_url($url);
+    if ($parts === false || empty($parts['scheme'])) return false;
+    return in_array(strtolower($parts['scheme']), ['http', 'https'], true);
+}
+
+function clean_public_url($url) {
+    $url = is_string($url) ? trim($url) : '';
+    return is_safe_public_url($url) ? $url : '';
+}
+
+function clean_public_urls($urls) {
+    if (!is_array($urls)) return [];
+    $clean = [];
+    foreach ($urls as $url) {
+        $url = clean_public_url($url);
+        if ($url !== '') $clean[] = $url;
+    }
+    return array_values(array_unique($clean));
+}
+
+function clean_css_color($value, $fallback = '#00f2ff') {
+    $value = is_string($value) ? trim($value) : '';
+    if (preg_match('/^#[0-9a-fA-F]{6}$/', $value) || preg_match('/^#[0-9a-fA-F]{3}$/', $value)) {
+        return $value;
+    }
+    return $fallback;
+}
+
 function json_response($data, $status = 200) {
     http_response_code($status);
     echo json_encode($data, JSON_UNESCAPED_UNICODE);
diff --git a/api/delete_files.php b/api/delete_files.php
index 5f99488..95f50c6 100644
--- a/api/delete_files.php
+++ b/api/delete_files.php
@@ -1,9 +1,10 @@
 <?php
 require_once 'config.php';
 require_once __DIR__ . '/error_config.php';
-session_start();
+start_secure_session();
 set_json_headers();
 require_auth();
+require_csrf();
 
 $method = $_SERVER['REQUEST_METHOD'];
 
diff --git a/api/learning.php b/api/learning.php
index 16c52f3..39de7ee 100644
--- a/api/learning.php
+++ b/api/learning.php
@@ -1,13 +1,31 @@
 <?php
 require_once 'config.php';
 require_once __DIR__ . '/error_config.php';
-session_start();
+start_secure_session();
 set_json_headers();
 
 define('LEARNING_FILE', DATA_DIR . '/learning.json');
 
 $method = $_SERVER['REQUEST_METHOD'];
 
+function clean_learning_content($content) {
+    $content = is_string($content) ? trim($content) : '';
+    $content = preg_replace_callback('/\]\(([^)]+)\)/', function($m) {
+        $url = trim($m[1]);
+        return is_safe_public_url($url) ? '](' . $url . ')' : '](#)';
+    }, $content);
+    $content = preg_replace_callback('/@video(\[[^\]]*\])?\(([^)]+)\)/', function($m) {
+        $attrs = $m[1] ?? '';
+        $url = trim($m[2]);
+        return is_safe_public_url($url) ? '@video' . $attrs . '(' . $url . ')' : '';
+    }, $content);
+    $content = preg_replace_callback('/\{color:([^}]+)\}([\s\S]+?)\{\/color\}/', function($m) {
+        $color = clean_css_color($m[1], '');
+        return $color === '' ? $m[2] : '{color:' . $color . '}' . $m[2] . '{/color}';
+    }, $content);
+    return $content;
+}
+
 // =====================================================
 // GET: 학습 일지 목록 또는 단일 글 (인증 불필요)
 // =====================================================
@@ -63,6 +81,7 @@ if ($method === 'GET') {
 }
 
 require_auth();
+require_csrf();
 
 // =====================================================
 // POST: 새 학습 일지 작성
@@ -71,7 +90,7 @@ if ($method === 'POST') {
     $input = get_json_input();
     
     $title = trim($input['title'] ?? '');
-    $content = trim($input['content'] ?? '');
+    $content = clean_learning_content($input['content'] ?? '');
     $categoryId = intval($input['category_id'] ?? 0);
     
     if (empty($title) || empty($content)) {
@@ -170,7 +189,7 @@ if ($method === 'PUT') {
                 $learnings[$key]['title'] = $title;
             }
             if (isset($input['content'])) {
-                $content = trim($input['content']);
+                $content = clean_learning_content($input['content']);
                 if ($content === '') json_response(['error' => '내용은 비울 수 없습니다'], 400);
                 $learnings[$key]['content'] = $content;
             }
diff --git a/api/profile.php b/api/profile.php
index beb0ee5..7698f32 100644
--- a/api/profile.php
+++ b/api/profile.php
@@ -1,7 +1,7 @@
 <?php
 require_once 'config.php';
 require_once __DIR__ . '/error_config.php';
-session_start();
+start_secure_session();
 set_json_headers();
 
 $method = $_SERVER['REQUEST_METHOD'];
@@ -49,6 +49,7 @@ if ($method === 'GET') {
 
 // 이하 수정은 인증 필요
 require_auth();
+require_csrf();
 
 // =====================================================
 // PUT: 프로필 전체 업데이트
@@ -66,7 +67,7 @@ if ($method === 'PUT') {
         'name' => trim($input['name'] ?? $current['name'] ?? ''),
         'title' => trim($input['title'] ?? $current['title'] ?? ''),
         'tagline' => trim($input['tagline'] ?? $current['tagline'] ?? ''),
-        'avatar' => trim($input['avatar'] ?? $current['avatar'] ?? ''),
+        'avatar' => clean_public_url($input['avatar'] ?? $current['avatar'] ?? ''),
         'bio' => trim($input['bio'] ?? $current['bio'] ?? ''),
         'location' => trim($input['location'] ?? $current['location'] ?? ''),
         'email' => trim($input['email'] ?? $current['email'] ?? ''),
@@ -101,7 +102,13 @@ if ($method === 'PUT') {
     }
     
     if (isset($input['social']) && is_array($input['social'])) {
-        $updated['social'] = array_merge($current['social'] ?? [], $input['social']);
+        $social = array_merge($current['social'] ?? [], $input['social']);
+        foreach (['github', 'linkedin', 'blog'] as $key) {
+            if (isset($social[$key])) {
+                $social[$key] = clean_public_url($social[$key]);
+            }
+        }
+        $updated['social'] = $social;
     }
     
     if (write_json_safe(PROFILE_FILE, $updated)) {
diff --git a/api/projects.php b/api/projects.php
index 0e457e3..65ac00a 100644
--- a/api/projects.php
+++ b/api/projects.php
@@ -1,7 +1,7 @@
 <?php
 require_once 'config.php';
 require_once __DIR__ . '/error_config.php';
-session_start();
+start_secure_session();
 set_json_headers();
 
 $method = $_SERVER['REQUEST_METHOD'];
@@ -11,14 +11,11 @@ $method = $_SERVER['REQUEST_METHOD'];
 // =====================================================
 function normalize_images($input) {
     if (isset($input['images']) && is_array($input['images'])) {
-        $images = array_values(array_filter(
-            array_map('trim', $input['images']),
-            fn($v) => $v !== ''
-        ));
-        return $images;
+        return clean_public_urls($input['images']);
     }
     if (isset($input['image']) && trim($input['image']) !== '') {
-        return [trim($input['image'])];
+        $image = clean_public_url($input['image']);
+        return $image === '' ? [] : [$image];
     }
     return [];
 }
@@ -80,6 +77,7 @@ if ($method === 'GET') {
 }
 
 require_auth();
+require_csrf();
 
 // =====================================================
 // POST: 새 프로젝트 추가
@@ -113,11 +111,11 @@ if ($method === 'POST') {
         'icon' => trim($input['icon'] ?? 'fa-solid fa-code'),
         'images' => $images,
         'image' => $images[0] ?? '',
-        'link' => trim($input['link'] ?? ''),
+        'link' => clean_public_url($input['link'] ?? ''),
         'stack' => $stack,
         'period_start' => trim($input['period_start'] ?? ''),
         'period_end' => trim($input['period_end'] ?? ''),
-        'video_url' => trim($input['video_url'] ?? ''),
+        'video_url' => clean_public_url($input['video_url'] ?? ''),
         'created_at' => date('Y-m-d')
     ];
     
@@ -150,7 +148,7 @@ if ($method === 'PUT') {
             $projects[$key]['label'] = trim($input['label'] ?? $project['label']);
             $projects[$key]['description'] = trim($input['description'] ?? $project['description']);
             $projects[$key]['icon'] = trim($input['icon'] ?? $project['icon']);
-            $projects[$key]['link'] = trim($input['link'] ?? $project['link']);
+            $projects[$key]['link'] = clean_public_url($input['link'] ?? $project['link']);
             
             if (isset($input['images']) || isset($input['image'])) {
                 $images = normalize_images($input);
@@ -169,7 +167,7 @@ if ($method === 'PUT') {
                 $projects[$key]['period_end'] = trim($input['period_end']);
             }
             if (isset($input['video_url'])) {
-                $projects[$key]['video_url'] = trim($input['video_url']);
+                $projects[$key]['video_url'] = clean_public_url($input['video_url']);
             }
             
             // 기존 demo_url 필드 제거
diff --git a/api/upload.php b/api/upload.php
index 2bd777b..6c2c4a8 100644
--- a/api/upload.php
+++ b/api/upload.php
@@ -1,9 +1,10 @@
 <?php
 require_once 'config.php';
 require_once __DIR__ . '/error_config.php';
-session_start();
+start_secure_session();
 set_json_headers();
 require_auth();
+require_csrf();
 
 if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
     json_response(['error' => 'POST만 허용됩니다'], 405);
@@ -225,5 +226,10 @@ if ($saved) {
     ]);
 } else {
     $err = error_get_last();
-    json_response(['error' => '파일 저장 실패', 'detail' => $err, 'target' => $target_path, 'tmp' => $file['tmp_name'], 'tmp_exists' => file_exists($file['tmp_name'])], 500);
+    error_log('Upload save failed: ' . json_encode([
+        'detail' => $err,
+        'target' => $target_path,
+        'tmp_exists' => file_exists($file['tmp_name'])
+    ], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE));
+    json_response(['error' => '파일 저장 실패'], 500);
 }
diff --git a/index.html b/index.html
index 13c57b6..87c3050 100644
--- a/index.html
+++ b/index.html
@@ -883,6 +883,7 @@ main { padding: 80px 8%; }
 <script>
 // ===== 상태 =====
 let isAdmin = false;
+let csrfToken = '';
 
 // ===== 테마 =====
 function applyTheme(theme) {
@@ -977,10 +978,19 @@ async function checkAuth() {
         const res = await fetch('api/auth.php?action=check');
         const data = await res.json();
         isAdmin = data.authenticated === true;
+        csrfToken = data.csrf_token || '';
         document.getElementById('adminControls').classList.toggle('hidden', !isAdmin);
     } catch (e) { isAdmin = false; }
 }
 
+function csrfHeaders(headers = {}) {
+    return csrfToken ? { ...headers, 'X-CSRF-Token': csrfToken } : headers;
+}
+
+function csrfFetch(url, options = {}) {
+    return fetch(url, { ...options, headers: csrfHeaders(options.headers || {}) });
+}
+
 function openLoginModal() {
     if (isAdmin) { logout(); return; }
     document.getElementById('loginModal').classList.add('active');
@@ -1004,6 +1014,7 @@ async function doLogin() {
         });
         const data = await res.json();
         if (data.success) {
+            csrfToken = data.csrf_token || csrfToken;
             isAdmin = true;
             document.getElementById('adminControls').classList.remove('hidden');
             closeLoginModal();
@@ -1017,7 +1028,8 @@ async function doLogin() {
 }
 
 async function logout() {
-    await fetch('api/auth.php?action=logout', { method: 'POST' });
+    await csrfFetch('api/auth.php?action=logout', { method: 'POST' });
+    csrfToken = '';
     isAdmin = false;
     document.getElementById('adminControls').classList.add('hidden');
     await loadProjects();
@@ -1069,6 +1081,8 @@ function renderProjects() {
     grid.innerHTML = pageProjects.map(p => {
         const images = (p.images && p.images.length > 0) ? p.images : (p.image ? [p.image] : []);
         const hasMultiple = images.length > 1;
+        const safeLink = sanitizeUrl(p.link);
+        const safeVideoUrl = sanitizeUrl(p.video_url);
         const cardId = `card-${p.id}`;
 
         return `
@@ -1087,7 +1101,7 @@ function renderProjects() {
                          onmouseleave="resumeSlideshow('${cardId}')">
                         ${images.map((img, i) => `
                             <div class="slideshow-slide ${i === 0 ? 'active' : ''}" 
-                                 style="background-image:url('${escapeHtml(img)}')"></div>
+                                 style="background-image:url('${escapeHtml(sanitizeUrl(img))}')"></div>
                         `).join('')}
                         ${hasMultiple ? `
                             <button class="slideshow-arrow prev" onclick="slideshowPrev('${cardId}')" aria-label="이전">
@@ -1125,10 +1139,10 @@ function renderProjects() {
                     </div>
                 ` : ''}
                 <div class="card-actions">
-                    ${p.link ? `<a href="${escapeHtml(p.link)}" class="btn-link git" target="_blank">
+                    ${safeLink ? `<a href="${escapeHtml(safeLink)}" class="btn-link git" target="_blank" rel="noopener noreferrer">
                         <i class="fa-brands fa-git-alt"></i><span class="btn-text"> 소스 코드</span>
                     </a>` : ''}
-                    ${p.video_url ? `<a href="${escapeHtml(p.video_url)}" class="btn-link video" target="_blank">
+                    ${safeVideoUrl ? `<a href="${escapeHtml(safeVideoUrl)}" class="btn-link video" target="_blank" rel="noopener noreferrer">
                         <i class="fa-solid fa-circle-play"></i><span class="btn-text"> 영상 보기</span>
                     </a>` : ''}
                 </div>
@@ -1734,7 +1748,7 @@ async function saveProject() {
             const formData = new FormData();
             formData.append('file', item.file);
             formData.append('project_title', title);
-            const res = await fetch('api/upload.php', { method: 'POST', body: formData });
+            const res = await csrfFetch('api/upload.php', { method: 'POST', body: formData });
             const result = await res.json();
             if (!result.success) throw new Error(result.error || '이미지 업로드 실패');
             URL.revokeObjectURL(item.url); // 메모리 해제
@@ -1753,7 +1767,7 @@ async function saveProject() {
             const formData = new FormData();
             formData.append('file', pendingVideoFile);
             formData.append('project_title', title);
-            const res = await fetch('api/upload.php', { method: 'POST', body: formData });
+            const res = await csrfFetch('api/upload.php', { method: 'POST', body: formData });
             const result = await res.json();
             if (!result.success) throw new Error(result.error || '영상 업로드 실패');
             videoUrl = result.url;
@@ -1784,13 +1798,13 @@ async function saveProject() {
         let res;
         if (id) {
             data.id = parseInt(id);
-            res = await fetch('api/projects.php', {
+            res = await csrfFetch('api/projects.php', {
                 method: 'PUT',
                 headers: { 'Content-Type': 'application/json' },
                 body: JSON.stringify(data)
             });
         } else {
-            res = await fetch('api/projects.php', {
+            res = await csrfFetch('api/projects.php', {
                 method: 'POST',
                 headers: { 'Content-Type': 'application/json' },
                 body: JSON.stringify(data)
@@ -1849,7 +1863,7 @@ async function deleteProject(id) {
     }
     
     try {
-        const res = await fetch(`api/projects.php?id=${id}`, { method: 'DELETE' });
+        const res = await csrfFetch(`api/projects.php?id=${id}`, { method: 'DELETE' });
         const result = await res.json();
         if (!result.success) {
             alert(result.error || '삭제 실패');
@@ -1858,16 +1872,14 @@ async function deleteProject(id) {
         
         if (deleteFolder && folderName) {
             try {
-                const fileRes = await fetch('api/delete_files.php', {
+                const fileRes = await csrfFetch('api/delete_files.php', {
                     method: 'POST',
                     headers: { 'Content-Type': 'application/json' },
                     body: JSON.stringify({ folder: folderName })
                 });
                 const fileResult = await fileRes.json();
-                if (fileResult.success) {
-                    if (fileResult.deleted_count > 0) {
-                        console.log(`이미지 폴더 정리: ${fileResult.deleted_count}개 파일 삭제됨`);
-                    }
+                if (!fileResult.success || fileResult.failed_count > 0) {
+                    alert('프로젝트는 삭제되었지만, 일부 파일 삭제에 실패했습니다.');
                 }
             } catch (e) {
                 alert('프로젝트는 삭제되었지만, 폴더 삭제 중 오류: ' + e.message);
@@ -1896,6 +1908,18 @@ function escapeHtml(str) {
         .replace(/"/g, '&quot;').replace(/'/g, '&#039;');
 }
 
+function sanitizeUrl(url) {
+    if (!url) return '';
+    const trimmed = String(url).trim();
+    if (/^uploads\/[A-Za-z0-9가-힣._~!$&'()*+,;=:@%/-]+$/u.test(trimmed) &&
+        !trimmed.includes('..') && !/(^|\/)\./.test(trimmed)) return trimmed;
+    try {
+        const parsed = new URL(trimmed, window.location.origin);
+        if (parsed.protocol === 'http:' || parsed.protocol === 'https:') return trimmed;
+    } catch (e) {}
+    return '';
+}
+
 // ESC 키로 모달 닫기 (바깥 클릭은 무시 - 실수 방지)
 document.addEventListener('keydown', (e) => {
     if (e.key === 'Escape') {
diff --git a/learning.html b/learning.html
index ee37eb5..103be66 100644
--- a/learning.html
+++ b/learning.html
@@ -1585,7 +1585,7 @@ footer {
         </div>
         <div class="form-group">
             <label>색상</label>
-            <input type="color" id="categoryColor" value="var(--primary)" style="height: 44px;">
+            <input type="color" id="categoryColor" value="#00f2ff" style="height: 44px;">
         </div>
         <div class="modal-actions">
             <button class="btn btn-primary" onclick="saveCategory()">
@@ -1981,6 +1981,7 @@ function toggleTheme() {
     applyTheme(saved || prefer);
 })();
 let isAdmin = false;
+let csrfToken = '';
 let categories = [];      // 모든 카테고리 (parent + child)
 let posts = [];
 let currentFilter = { type: 'all', value: null };
@@ -2013,10 +2014,7 @@ function renderMarkdown(src) {
         parts.forEach(p => {
             const m = p.match(/^w(?:idth)?\s*=\s*(.+)$/i);
             if (m) {
-                let w = m[1].trim();
-                // 숫자만 있으면 px 추가
-                if (/^\d+$/.test(w)) w = w + 'px';
-                result.width = w;
+                result.width = sanitizeMediaWidth(m[1].trim());
                 return;
             }
             if (/^(left|center|right)$/i.test(p)) {
@@ -2040,6 +2038,8 @@ function renderMarkdown(src) {
     src = src.replace(
         /@video(?:\[([^\]]*)\])?\(([^)]+)\)/g,
         function(match, attrStr, url) {
+            const safeUrl = sanitizeUrl(url);
+            if (!safeUrl) return '';
             const attrs = parseAttrs(attrStr || '');
             // width와 align은 wrap에 적용 (video 자체가 아님)
             const styles = [];
@@ -2048,7 +2048,7 @@ function renderMarkdown(src) {
             if (alignS) styles.push(alignS.replace(/;$/, ''));
             styles.push('max-width:100%');
             const wrapStyle = `style="${styles.join(';')}"`;
-            return `<div class="md-video-wrap" ${wrapStyle}><video class="md-video" preload="metadata" src="${url.trim()}"></video></div>`;
+            return `<div class="md-video-wrap" ${wrapStyle}><video class="md-video" preload="metadata" src="${escapeHtml(safeUrl)}"></video></div>`;
         }
     );
     
@@ -2057,13 +2057,15 @@ function renderMarkdown(src) {
     src = src.replace(
         /!\[([^\]]*?)\|([^\]]+)\]\(([^)]+)\)/g,
         function(match, alt, attrStr, url) {
+            const safeUrl = sanitizeUrl(url);
+            if (!safeUrl) return '';
             const attrs = parseAttrs(attrStr);
             const styles = [];
             if (attrs.width) styles.push(`width:${attrs.width}`);
             styles.push('max-width:100%');
             const alignS = alignStyle(attrs.align);
             if (alignS) styles.push(alignS.replace(/;$/, ''));
-            return `<img src="${url.trim()}" alt="${alt}" style="${styles.join(';')};">`;
+            return `<img src="${escapeHtml(safeUrl)}" alt="${escapeHtml(alt)}" style="${styles.join(';')};">`;
         }
     );
     
@@ -2091,10 +2093,12 @@ function renderMarkdown(src) {
     src = src.replace(/==([^=\n\[]+)==/g, '<mark>$1</mark>');
     
     // ===== 5) 색상: {color:#ff0000}text{/color} =====
-    src = src.replace(/\{color:(#[0-9a-fA-F]{3,8}|[a-zA-Z]+)\}([\s\S]+?)\{\/color\}/g, 
-        '<span class="md-color" style="color:$1">$2</span>');
+    src = src.replace(/\{color:([^}]+)\}([\s\S]+?)\{\/color\}/g, function(match, color, text) {
+        const safeColor = sanitizeCssColor(color);
+        return safeColor ? `<span class="md-color" style="color:${safeColor}">${text}</span>` : text;
+    });
     
-    return DOMPurify.sanitize(marked.parse(src));
+    return sanitizeAllowedStyles(DOMPurify.sanitize(marked.parse(src)));
 }
 
 // 렌더 후 비디오에 커스텀 컨트롤 부착
@@ -2406,8 +2410,7 @@ function addMediaToolbar(wrap, kind, curWidth, curAlign) {
 }
 
 function applyWidth(wrap, widthVal, kind) {
-    // 숫자만 입력되면 px 추가
-    if (/^\d+$/.test(widthVal)) widthVal = widthVal + 'px';
+    widthVal = sanitizeMediaWidth(widthVal);
     wrap.style.width = widthVal || '';
     // 툴바 input 동기화
     const input = wrap.querySelector('.md-toolbar-size-input');
@@ -2486,10 +2489,19 @@ async function checkAuth() {
         const res = await fetch('api/auth.php?action=check');
         const data = await res.json();
         isAdmin = data.authenticated === true;
+        csrfToken = data.csrf_token || '';
         document.body.classList.toggle('admin-on', isAdmin);
     } catch (e) { isAdmin = false; }
 }
 
+function csrfHeaders(headers = {}) {
+    return csrfToken ? { ...headers, 'X-CSRF-Token': csrfToken } : headers;
+}
+
+function csrfFetch(url, options = {}) {
+    return fetch(url, { ...options, headers: csrfHeaders(options.headers || {}) });
+}
+
 function openLoginModal() {
     if (isAdmin) { logout(); return; }
     document.getElementById('loginModal').classList.add('active');
@@ -2511,6 +2523,7 @@ async function doLogin() {
         });
         const data = await res.json();
         if (data.success) {
+            csrfToken = data.csrf_token || csrfToken;
             isAdmin = true;
             document.body.classList.add('admin-on');
             closeLoginModal();
@@ -2522,7 +2535,8 @@ async function doLogin() {
     }
 }
 async function logout() {
-    await fetch('api/auth.php?action=logout', { method: 'POST' });
+    await csrfFetch('api/auth.php?action=logout', { method: 'POST' });
+    csrfToken = '';
     isAdmin = false;
     document.body.classList.remove('admin-on');
 }
@@ -2746,7 +2760,7 @@ function renderCategoryList() {
                      onclick="onParentClick(${parent.id})">
                     <div class="cat-name">
                         <i class="fa-solid fa-chevron-right cat-toggle"></i>
-                        <span class="cat-dot" style="background: ${escapeHtml(parent.color)};"></span>
+                        <span class="cat-dot" style="background: ${escapeHtml(sanitizeCssColor(parent.color, '#00f2ff'))};"></span>
                         <span class="cat-label">${escapeHtml(parent.name)}</span>
                     </div>
                     <div style="display: flex; align-items: center; gap: 6px;">
@@ -2781,7 +2795,7 @@ function renderCategoryList() {
                     <div class="cat-item ${isActive ? 'active' : ''}" 
                          onclick="setFilter('category', ${child.id})">
                         <div class="cat-name">
-                            <span class="cat-dot" style="background: ${escapeHtml(child.color)};"></span>
+                            <span class="cat-dot" style="background: ${escapeHtml(sanitizeCssColor(child.color, '#00f2ff'))};"></span>
                             <span class="cat-label">${escapeHtml(child.name)}</span>
                         </div>
                         <div style="display: flex; align-items: center; gap: 6px;">
@@ -2909,10 +2923,6 @@ function renderPosts() {
             const postDate = (p.created_at || '').trim();
             return postDate === dateFilter;
         });
-        // 디버그: 일치하는 글 없으면 콘솔에 출력
-        if (filtered.length === 0) {
-            console.log('[날짜 필터]', dateFilter, '- 전체 글의 날짜:', posts.map(p => p.created_at));
-        }
     }
     
     // 검색 (scope에 따라 분기)
@@ -2959,7 +2969,7 @@ function renderPosts() {
     list.innerHTML = filtered.map(p => {
         const cat = getCategoryById(p.category_id);
         const parent = cat ? getCategoryById(cat.parent_id) : null;
-        const catColor = cat ? cat.color : 'var(--primary)';
+        const catColor = cat ? sanitizeCssColor(cat.color, '#00f2ff') : '#00f2ff';
         const preview = stripMarkdown(p.content || '').slice(0, 200);
         
         return `
@@ -2972,7 +2982,7 @@ function renderPosts() {
                 </div>
                 ${cat ? `
                     <div class="post-cat-pill">
-                        <span class="cat-dot" style="background: ${escapeHtml(cat.color)};"></span>
+                        <span class="cat-dot" style="background: ${escapeHtml(sanitizeCssColor(cat.color, '#00f2ff'))};"></span>
                         ${parent ? `<span style="opacity: 0.7;">${escapeHtml(parent.name)} ›</span>` : ''}
                         ${escapeHtml(cat.name)}
                     </div>
@@ -3012,7 +3022,7 @@ function openPostDetail(id) {
     if (cat) {
         metaParts.push(`
             <div class="post-cat-pill">
-                <span class="cat-dot" style="background: ${escapeHtml(cat.color)};"></span>
+                <span class="cat-dot" style="background: ${escapeHtml(sanitizeCssColor(cat.color, '#00f2ff'))};"></span>
                 ${parent ? `<span style="opacity: 0.7;">${escapeHtml(parent.name)} ›</span>` : ''}
                 ${escapeHtml(cat.name)}
             </div>
@@ -3109,7 +3119,7 @@ async function deleteCurrentPost() {
     
     try {
         // 글 삭제
-        const res = await fetch(`api/learning.php?id=${currentDetailId}`, { method: 'DELETE' });
+        const res = await csrfFetch(`api/learning.php?id=${currentDetailId}`, { method: 'DELETE' });
         const result = await res.json();
         if (!result.success) {
             alert(result.error || '글 삭제 실패');
@@ -3119,16 +3129,13 @@ async function deleteCurrentPost() {
         // 첨부 파일 삭제 (선택했을 때)
         if (deleteFiles && attachedUrls.length > 0) {
             try {
-                const fileRes = await fetch('api/delete_files.php', {
+                const fileRes = await csrfFetch('api/delete_files.php', {
                     method: 'POST',
                     headers: { 'Content-Type': 'application/json' },
                     body: JSON.stringify({ urls: attachedUrls })
                 });
                 const fileResult = await fileRes.json();
                 if (fileResult.success) {
-                    if (fileResult.deleted_count > 0) {
-                        console.log(`첨부 파일 ${fileResult.deleted_count}개 삭제됨`);
-                    }
                     if (fileResult.failed_count > 0) {
                         alert(`글은 삭제되었지만, ${fileResult.failed_count}개 파일 삭제에 실패했습니다.`);
                     }
@@ -3523,9 +3530,9 @@ function buildMediaAttrs() {
     const parts = [];
     let width = '';
     if (widthSel === 'custom') {
-        width = widthCust;
+        width = sanitizeMediaWidth(widthCust);
     } else if (widthSel) {
-        width = widthSel;
+        width = sanitizeMediaWidth(widthSel);
     }
     if (width) parts.push(`w=${width}`);
     if (align) parts.push(align);
@@ -3568,11 +3575,11 @@ function insertAttachFile() {
 }
 
 function insertMediaFromUrl() {
-    const url = document.getElementById('imageInsertUrl').value.trim();
+    const url = sanitizeUrl(document.getElementById('imageInsertUrl').value.trim());
     const alt = document.getElementById('imageInsertAlt').value.trim();
     const kind = document.getElementById('imageInsertKind').value;
     if (!url) {
-        showAlert('imageInsertAlert', 'URL을 입력해주세요', 'error');
+        showAlert('imageInsertAlert', 'http, https, uploads/ 경로만 사용할 수 있습니다', 'error');
         return;
     }
     insertAtCursor(buildMediaMarkdown(kind, url, alt));
@@ -3667,7 +3674,7 @@ async function uploadPendingMedia(content) {
             const formData = new FormData();
             formData.append('file', file);
             formData.append('project_title', 'learning');
-            const res = await fetch('api/upload.php', { method: 'POST', body: formData });
+            const res = await csrfFetch('api/upload.php', { method: 'POST', body: formData });
             const result = await res.json();
             
             if (result.success && result.url) {
@@ -3699,7 +3706,7 @@ async function uploadPendingMedia(content) {
 // ===== 색상 선택 =====
 const COLOR_PALETTE = [
     // 세이지/민트 계열
-    'var(--primary)', '#3d6b50', '#8ab89a', '#B2E2D2',
+    '#00f2ff', '#3d6b50', '#8ab89a', '#B2E2D2',
     // 웜 뉴트럴
     '#b07a20', '#c9a050', '#c8856a', '#9e6b52',
     // 레드/핑크 (핀포인트)
@@ -3751,7 +3758,8 @@ function closeColorPicker() {
     document.getElementById('colorPickerModal').classList.remove('active');
 }
 function applyColor(color) {
-    wrapSelection(`{color:${color}}`, '{/color}', '');
+    const safeColor = sanitizeCssColor(color);
+    if (safeColor) wrapSelection(`{color:${safeColor}}`, '{/color}', '');
     closeColorPicker();
 }
 
@@ -3847,13 +3855,13 @@ async function savePost() {
         let res;
         if (id) {
             data.id = parseInt(id);
-            res = await fetch('api/learning.php', {
+            res = await csrfFetch('api/learning.php', {
                 method: 'PUT',
                 headers: { 'Content-Type': 'application/json' },
                 body: JSON.stringify(data)
             });
         } else {
-            res = await fetch('api/learning.php', {
+            res = await csrfFetch('api/learning.php', {
                 method: 'POST',
                 headers: { 'Content-Type': 'application/json' },
                 body: JSON.stringify(data)
@@ -3900,7 +3908,7 @@ function openCategoryModal(cat = null) {
         document.getElementById('categoryModalTitle').textContent = '카테고리 수정';
         document.getElementById('categoryId').value = cat.id;
         document.getElementById('categoryName').value = cat.name;
-        document.getElementById('categoryColor').value = cat.color || 'var(--primary)';
+        document.getElementById('categoryColor').value = sanitizeCssColor(cat.color, '#00f2ff');
         parentSel.value = cat.parent_id || '';
         // 자식이 있으면 부모 변경 비활성화
         const hasChildren = categories.some(c => c.parent_id === cat.id);
@@ -3912,7 +3920,7 @@ function openCategoryModal(cat = null) {
         document.getElementById('categoryModalTitle').textContent = '카테고리 추가';
         document.getElementById('categoryId').value = '';
         document.getElementById('categoryName').value = '';
-        document.getElementById('categoryColor').value = 'var(--primary)';
+        document.getElementById('categoryColor').value = '#00f2ff';
         parentSel.value = '';
         parentSel.disabled = false;
     }
@@ -3966,7 +3974,7 @@ async function deleteCategory(id) {
     if (!confirm(msg)) return;
     
     try {
-        const res = await fetch(`api/categories.php?id=${id}`, { method: 'DELETE' });
+        const res = await csrfFetch(`api/categories.php?id=${id}`, { method: 'DELETE' });
         const result = await res.json();
         if (result.success) {
             // 현재 필터가 영향받으면 전체로
@@ -4002,13 +4010,13 @@ async function saveCategory() {
         let res;
         if (id) {
             payload.id = parseInt(id);
-            res = await fetch('api/categories.php', {
+            res = await csrfFetch('api/categories.php', {
                 method: 'PUT',
                 headers: { 'Content-Type': 'application/json' },
                 body: JSON.stringify(payload)
             });
         } else {
-            res = await fetch('api/categories.php', {
+            res = await csrfFetch('api/categories.php', {
                 method: 'POST',
                 headers: { 'Content-Type': 'application/json' },
                 body: JSON.stringify(payload)
@@ -4049,6 +4057,67 @@ function escapeHtml(str) {
         .replace(/"/g, '&quot;').replace(/'/g, '&#039;');
 }
 
+function sanitizeUrl(url) {
+    if (!url) return '';
+    const trimmed = String(url).trim();
+    if (/^uploads\/[A-Za-z0-9가-힣._~!$&'()*+,;=:@%/-]+$/u.test(trimmed) &&
+        !trimmed.includes('..') && !/(^|\/)\./.test(trimmed)) return trimmed;
+    try {
+        const parsed = new URL(trimmed, window.location.origin);
+        if (parsed.protocol === 'http:' || parsed.protocol === 'https:') return trimmed;
+    } catch (e) {}
+    return '';
+}
+
+function sanitizeCssColor(color, fallback = '') {
+    const trimmed = String(color || '').trim();
+    return /^#[0-9a-fA-F]{3}$/.test(trimmed) || /^#[0-9a-fA-F]{6}$/.test(trimmed) ? trimmed : fallback;
+}
+
+function sanitizeMediaWidth(width) {
+    let value = String(width || '').trim();
+    if (/^\d+$/.test(value)) value += 'px';
+    const px = value.match(/^(\d{1,4})px$/);
+    if (px) return Math.min(Math.max(parseInt(px[1], 10), 40), 1200) + 'px';
+    const pct = value.match(/^(\d{1,3})%$/);
+    if (pct) return Math.min(Math.max(parseInt(pct[1], 10), 1), 100) + '%';
+    return '';
+}
+
+function sanitizeAllowedStyles(html) {
+    const template = document.createElement('template');
+    template.innerHTML = html;
+    template.content.querySelectorAll('[style]').forEach(el => {
+        const allowed = [];
+        const declarations = String(el.getAttribute('style') || '').split(';');
+        declarations.forEach(decl => {
+            const [rawProp, ...rawValueParts] = decl.split(':');
+            if (!rawProp || rawValueParts.length === 0) return;
+            const prop = rawProp.trim().toLowerCase();
+            const value = rawValueParts.join(':').trim();
+            if (prop === 'width') {
+                const width = sanitizeMediaWidth(value);
+                if (width) allowed.push(`width:${width}`);
+            } else if (prop === 'max-width' && value === '100%') {
+                allowed.push('max-width:100%');
+            } else if (prop === 'display' && value === 'block') {
+                allowed.push('display:block');
+            } else if ((prop === 'margin-left' || prop === 'margin-right') && /^(auto|0)$/.test(value)) {
+                allowed.push(`${prop}:${value}`);
+            } else if (prop === 'color') {
+                const color = sanitizeCssColor(value);
+                if (color) allowed.push(`color:${color}`);
+            }
+        });
+        if (allowed.length > 0) {
+            el.setAttribute('style', allowed.join(';'));
+        } else {
+            el.removeAttribute('style');
+        }
+    });
+    return template.innerHTML;
+}
+
 // ESC / 백스페이스로 모달 닫기
 document.addEventListener('keydown', (e) => {
     if (e.key === 'Escape') {
diff --git a/profile.html b/profile.html
index f6941a0..d5fc222 100644
--- a/profile.html
+++ b/profile.html
@@ -695,6 +695,7 @@ function toggleTheme() {
     applyTheme(saved || prefer);
 })();
 let isAdmin = false;
+let csrfToken = '';
 let profile = null;
 
 async function init() {
@@ -707,12 +708,21 @@ async function checkAuth() {
         const res = await fetch('api/auth.php?action=check');
         const data = await res.json();
         isAdmin = data.authenticated === true;
+        csrfToken = data.csrf_token || '';
         document.querySelectorAll('.admin-controls').forEach(el => {
             el.classList.toggle('hidden', !isAdmin);
         });
     } catch (e) { isAdmin = false; }
 }
 
+function csrfHeaders(headers = {}) {
+    return csrfToken ? { ...headers, 'X-CSRF-Token': csrfToken } : headers;
+}
+
+function csrfFetch(url, options = {}) {
+    return fetch(url, { ...options, headers: csrfHeaders(options.headers || {}) });
+}
+
 async function loadProfile() {
     try {
         const res = await fetch('api/profile.php');
@@ -734,7 +744,7 @@ function renderProfile() {
 
     const avatarEl = document.getElementById('avatarEl');
     if (profile.avatar) {
-        avatarEl.style.backgroundImage = `url('${escapeAttr(profile.avatar)}')`;
+        avatarEl.style.backgroundImage = `url('${escapeAttr(sanitizeUrl(profile.avatar))}')`;
         avatarEl.style.backgroundSize = 'cover';
         avatarEl.style.backgroundPosition = 'center';
         avatarEl.innerHTML = '';
@@ -818,8 +828,10 @@ function renderProfile() {
                 </a>
             `;
         }
+        const safeHref = sanitizeUrl(c.href);
+        if (!safeHref) return '';
         return `
-            <a href="${escapeAttr(c.href)}" class="contact-card" target="_blank">
+            <a href="${escapeAttr(safeHref)}" class="contact-card" target="_blank" rel="noopener noreferrer">
                 <i class="${c.icon}"></i>
                 <span class="label">${c.label}</span>
                 <span class="value">${escapeHtml(c.value)}</span>
@@ -1040,7 +1052,7 @@ async function saveProfile() {
     };
 
     try {
-        const res = await fetch('api/profile.php', {
+        const res = await csrfFetch('api/profile.php', {
             method: 'PUT',
             headers: { 'Content-Type': 'application/json' },
             body: JSON.stringify(data)
@@ -1071,6 +1083,18 @@ function escapeHtml(str) {
 }
 function escapeAttr(str) { return escapeHtml(str); }
 
+function sanitizeUrl(url) {
+    if (!url) return '';
+    const trimmed = String(url).trim();
+    if (/^uploads\/[A-Za-z0-9가-힣._~!$&'()*+,;=:@%/-]+$/u.test(trimmed) &&
+        !trimmed.includes('..') && !/(^|\/)\./.test(trimmed)) return trimmed;
+    try {
+        const parsed = new URL(trimmed, window.location.origin);
+        if (parsed.protocol === 'http:' || parsed.protocol === 'https:') return trimmed;
+    } catch (e) {}
+    return '';
+}
+
 // ESC 키로 모달 닫기 (바깥 클릭 닫기 제거)
 document.addEventListener('keydown', (e) => {
     if (e.key === 'Escape') {