diff --git a/package-lock.json b/package-lock.json
index 601570d..11d135d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -10,6 +10,7 @@
       "dependencies": {
         "@types/uuid": "^10.0.0",
         "clsx": "^2.1.1",
+        "dompurify": "^3.3.1",
         "jsqr": "1.4.0",
         "lucide-react": "^0.344.0",
         "prop-types": "15.8.1",
@@ -80,7 +81,6 @@
       "integrity": "sha512-e7jT4DxYvIDLk1ZHmU/m/mB19rex9sv0c2ftBtjSBv+kVM/902eh0fINUzD7UwLLNR+jU585GxUJ8/EBfAM5fw==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "@babel/code-frame": "^7.27.1",
         "@babel/generator": "^7.28.5",
@@ -2891,7 +2891,6 @@
       "integrity": "sha512-LCCV0HdSZZZb34qifBsyWlUmok6W7ouER+oQIGBScS8EsZsQbrtFTUrDX4hOl+CS6p7cnNC4td+qrSVGSCTUfQ==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "undici-types": "~6.21.0"
       }
@@ -2907,7 +2906,7 @@
       "version": "2.0.7",
       "resolved": "https://registry.npmjs.org/@types/trusted-types/-/trusted-types-2.0.7.tgz",
       "integrity": "sha512-ScaPdn1dQczgbl0QFTeTOmVHFULt394XJgOQNoyVhZ6r2vLnMLJfBPd53SB52T/3G36VI1/g2MZaX0cwDuXsfw==",
-      "dev": true,
+      "devOptional": true,
       "license": "MIT"
     },
     "node_modules/@types/uuid": {
@@ -2956,7 +2955,6 @@
       "integrity": "sha512-B/gBuNg5SiMTrPkC+A2+cW0RszwxYmn6VYxB/inlBStS5nx6xHIt/ehKRhIMhqusl7a8LjQoZnjCs5vhwxOQ1g==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "fast-deep-equal": "^3.1.3",
         "fast-uri": "^3.0.1",
@@ -3165,7 +3163,6 @@
         }
       ],
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "baseline-browser-mapping": "^2.9.0",
         "caniuse-lite": "^1.0.30001759",
@@ -3624,6 +3621,15 @@
         "csstype": "^3.0.2"
       }
     },
+    "node_modules/dompurify": {
+      "version": "3.3.1",
+      "resolved": "https://registry.npmjs.org/dompurify/-/dompurify-3.3.1.tgz",
+      "integrity": "sha512-qkdCKzLNtrgPFP1Vo+98FRzJnBRGe4ffyCea9IwHB1fyxPOeNTHpLKYGd4Uk9xvNoH0ZoOjwZxNptyMwqrId1Q==",
+      "license": "(MPL-2.0 OR Apache-2.0)",
+      "optionalDependencies": {
+        "@types/trusted-types": "^2.0.7"
+      }
+    },
     "node_modules/dunder-proto": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/dunder-proto/-/dunder-proto-1.0.1.tgz",
@@ -5244,7 +5250,6 @@
       "resolved": "https://registry.npmjs.org/react/-/react-18.3.1.tgz",
       "integrity": "sha512-wS+hAgJShR0KhEvPJArfuPVN1+Hz1t0Y6n5jLrGQbkb4urgPE/0Rve+1kMB1v/oWgHgm4WIcV+i7F2pTVj+2iQ==",
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "loose-envify": "^1.1.0"
       },
@@ -5257,7 +5262,6 @@
       "resolved": "https://registry.npmjs.org/react-dom/-/react-dom-18.3.1.tgz",
       "integrity": "sha512-5m4nQKp+rZRb09LNH59GM4BxTh9251/ylbKIbpe7TpGxfJ+9kv6BLkLBXIjjspbgbnIBNqlI23tRnTWT0snUIw==",
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "loose-envify": "^1.1.0",
         "scheduler": "^0.23.2"
@@ -6178,7 +6182,6 @@
       "integrity": "sha512-t/R3R/n0MSwnnazuPpPNVO60LX0SKL45pyl9YlvxIdkH0Of7D5qM2EVe+yASRIlY5pZ73nclYJfNANGWPwFDZw==",
       "dev": true,
       "license": "BSD-2-Clause",
-      "peer": true,
       "dependencies": {
         "@jridgewell/source-map": "^0.3.3",
         "acorn": "^8.15.0",
@@ -6506,7 +6509,6 @@
       "integrity": "sha512-+Oxm7q9hDoLMyJOYfUYBuHQo+dkAloi33apOPP56pzj+vsdJDzr+j1NISE5pyaAuKL4A3UD34qd0lx5+kfKp2g==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "esbuild": "^0.25.0",
         "fdir": "^6.4.4",
@@ -6903,7 +6905,6 @@
       "integrity": "sha512-fS6iqSPZDs3dr/y7Od6y5nha8dW1YnbgtsyotCVvoFGKbERG++CVRFv1meyGDE1SNItQA8BrnCw7ScdAhRJ3XQ==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "bin": {
         "rollup": "dist/bin/rollup"
       },
diff --git a/package.json b/package.json
index 5cb82ea..11ee598 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,7 @@
   "dependencies": {
     "@types/uuid": "^10.0.0",
     "clsx": "^2.1.1",
+    "dompurify": "^3.3.1",
     "jsqr": "1.4.0",
     "lucide-react": "^0.344.0",
     "prop-types": "15.8.1",
diff --git a/src/components/AnnouncementModal.tsx b/src/components/AnnouncementModal.tsx
index 0322347..1ec2a27 100644
--- a/src/components/AnnouncementModal.tsx
+++ b/src/components/AnnouncementModal.tsx
@@ -1,8 +1,63 @@
 import React, { useEffect, useState } from 'react';
 import { X, Megaphone } from 'lucide-react';
+import DOMPurify from 'dompurify';
 
 const ANNOUNCEMENT_URL = 'https://www.transmtf.com/api/announcement/tmtf_b243d43f97b51b4fef747016';
 const STORAGE_KEY = 'tmtf_announcement_hash';
+const ANNOUNCEMENT_ALLOWED_TAGS = [
+  'p', 'br', 'strong', 'em', 'b', 'i', 'u',
+  'ul', 'ol', 'li',
+  'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
+  'table', 'thead', 'tbody', 'tr', 'th', 'td',
+  'span', 'div',
+  'a', 'blockquote', 'code', 'pre', 'hr', 'img'
+];
+const ANNOUNCEMENT_ALLOWED_ATTR = [
+  'href', 'title', 'target', 'rel', 'src', 'alt',
+  'colspan', 'rowspan', 'scope'
+];
+const ANNOUNCEMENT_SAFE_REL_TOKENS = ['noopener', 'noreferrer'] as const;
+const ANNOUNCEMENT_SANITIZE_CONFIG = {
+  ALLOWED_TAGS: ANNOUNCEMENT_ALLOWED_TAGS,
+  ALLOWED_ATTR: ANNOUNCEMENT_ALLOWED_ATTR,
+  ALLOW_DATA_ATTR: false,
+  FORBID_TAGS: ['style', 'script', 'iframe', 'object', 'embed', 'form', 'input', 'button', 'textarea', 'select', 'svg', 'math'],
+  FORBID_ATTR: ['style'],
+  ALLOWED_URI_REGEXP: /^(?:https:|mailto:|tel:|\/(?!\/))/i,
+};
+
+function enforceSafeLinkTargets(html: string): string {
+  const template = document.createElement('template');
+  template.innerHTML = html;
+
+  template.content.querySelectorAll('a[target]').forEach((anchor) => {
+    const target = anchor.getAttribute('target');
+    if (target == null) return;
+
+    const normalizedTarget = target.trim().toLowerCase();
+    if (normalizedTarget !== '_blank') {
+      anchor.removeAttribute('target');
+      return;
+    }
+
+    anchor.setAttribute('target', '_blank');
+    const relTokens = new Set(
+      (anchor.getAttribute('rel') ?? '')
+        .split(/\s+/)
+        .map(token => token.trim().toLowerCase())
+        .filter(Boolean)
+    );
+    ANNOUNCEMENT_SAFE_REL_TOKENS.forEach(token => relTokens.add(token));
+    anchor.setAttribute('rel', Array.from(relTokens).join(' '));
+  });
+
+  return template.innerHTML;
+}
+
+function sanitizeAnnouncementHtml(html: string): string {
+  const sanitized = DOMPurify.sanitize(html, ANNOUNCEMENT_SANITIZE_CONFIG);
+  return enforceSafeLinkTargets(sanitized);
+}
 
 async function hashContent(content: string): Promise<string> {
   const buf = await crypto.subtle.digest('SHA-256', new TextEncoder().encode(content));
@@ -23,12 +78,25 @@ const AnnouncementModal: React.FC = () => {
         const text = (await res.text()).trim();
         if (!text) return;
 
-        const hash = await hashContent(text);
-        if (hash !== localStorage.getItem(STORAGE_KEY)) {
-          localStorage.setItem(STORAGE_KEY, hash);
-          setContent(text);
-          setVisible(true);
+        const sanitized = sanitizeAnnouncementHtml(text).trim();
+        if (!sanitized) return;
+
+        const currentHash = await hashContent(sanitized);
+        const storedHash = localStorage.getItem(STORAGE_KEY);
+
+        // Backward compatibility: older versions stored hash of raw content.
+        if (storedHash === currentHash) return;
+        if (storedHash) {
+          const legacyHash = await hashContent(text);
+          if (storedHash === legacyHash) {
+            localStorage.setItem(STORAGE_KEY, currentHash);
+            return;
+          }
         }
+
+        localStorage.setItem(STORAGE_KEY, currentHash);
+        setContent(sanitized);
+        setVisible(true);
       } catch {
         // 公告是非关键功能，静默失败
       }