diff --git a/packages/ui-default/backendlib/markdown-it-xss.js b/packages/ui-default/backendlib/markdown-it-xss.ts
similarity index 73%
rename from packages/ui-default/backendlib/markdown-it-xss.js
rename to packages/ui-default/backendlib/markdown-it-xss.ts
index f554dd797..2dba4cc30 100644
--- a/packages/ui-default/backendlib/markdown-it-xss.js
+++ b/packages/ui-default/backendlib/markdown-it-xss.ts
@@ -1,4 +1,7 @@
-const Xss = require('xss');
+import * as Xss from 'xss';
+
+const stack = [];
+let isFull = false;
 
 const xss = new Xss.FilterXSS({
   whiteList: {
@@ -73,8 +76,35 @@ const xss = new Xss.FilterXSS({
     if (name === 'class') return value.replace(/badge/g, 'xss-badge');
     return value;
   },
+  onTag(tag, html, options) {
+    if (!options.isWhite || !isFull) return null;
+    if (!options.isClosing) {
+      stack.push(tag);
+      return null;
+    }
+    if (stack.length === 0) return `</${tag}>`; // 没有标签可供闭合
+    if (stack[stack.length - 1] === tag) {
+      stack.pop(); // 正常关闭
+      return null;
+    }
+    if (stack.length - 2 >= 0 && stack[stack.length - 2] === tag) {
+      // 可能丢失了一个结束标签
+      stack.pop();
+      stack.pop();
+      return null;
+    }
+    return `</${tag}>`; // 可能多出了一个结束标签
+  },
 });
 
+xss.process = ((original) => (html: string, full: boolean = false) => {
+  stack.length = 0;
+  isFull = full;
+  const res = original(html);
+  if (!full) return res;
+  return res + stack.map((i) => `</${i}>`).join('');
+})(xss.process.bind(xss));
+
 function xssProtector(md) {
   function protector(state) {
     for (let i = 0; i < state.tokens.length; i++) {
diff --git a/packages/ui-default/backendlib/template.js b/packages/ui-default/backendlib/template.js
index 0570b4e18..9b127f17e 100644
--- a/packages/ui-default/backendlib/template.js
+++ b/packages/ui-default/backendlib/template.js
@@ -63,8 +63,8 @@ class Nunjucks extends nunjucks.Environment {
     this.addFilter('dumpYaml', (self) => yaml.dump(self));
     this.addFilter('serialize', (self, ignoreFunction = true) => serialize(self, { ignoreFunction }));
     this.addFilter('assign', (self, data) => Object.assign(self, data));
-    this.addFilter('markdown', (self, html = false) => markdown.render(self, html));
-    this.addFilter('markdownInline', (self, html = false) => markdown.renderInline(self, html));
+    this.addFilter('markdown', (self, html = false) => xss.process(markdown.render(self, html), true));
+    this.addFilter('markdownInline', (self, html = false) => xss.process(markdown.renderInline(self, html), true));
     this.addFilter('ansi', (self) => misc.ansiToHtml(self));
     this.addFilter('base64_encode', (s) => Buffer.from(s).toString('base64'));
     this.addFilter('base64_decode', (s) => Buffer.from(s, 'base64').toString());
@@ -87,7 +87,7 @@ class Nunjucks extends nunjucks.Environment {
         else s = s[langs[0]];
       }
       if (s instanceof Array) s = buildContent(s, html ? 'html' : 'markdown', (str) => str.translate(language));
-      return html ? xss.process(s) : markdown.render(s);
+      return xss.process(html ? s : markdown.render(s), true);
     });
     this.addFilter('log', (self) => {
       console.log(self);
diff --git a/packages/ui-default/package.json b/packages/ui-default/package.json
index 29b64d53e..d2e0eca34 100644
--- a/packages/ui-default/package.json
+++ b/packages/ui-default/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@hydrooj/ui-default",
-  "version": "4.31.8",
+  "version": "4.31.9",
   "author": "undefined <i@undefined.moe>",
   "license": "AGPL-3.0",
   "main": "hydro.js",