diff --git a/Update.json b/Update.json
index fbf81e36..cc93908a 100644
--- a/Update.json
+++ b/Update.json
@@ -3348,6 +3348,17 @@
                 }
             ],
             "Notes": "v3 显然需要在新年第一天发布("
+        },
+        "3.1.1": {
+            "UpdateDate": 1771489733913,
+            "Prerelease": true,
+            "UpdateContents": [
+                {
+                    "PR": 910,
+                    "Description": "Fix XSS in post title rendering"
+                }
+            ],
+            "Notes": "Fixed a stored XSS vulnerability in discussion thread post titles."
         }
     }
 }
\ No newline at end of file
diff --git a/XMOJ.user.js b/XMOJ.user.js
index aba3fd3d..0b120687 100644
--- a/XMOJ.user.js
+++ b/XMOJ.user.js
@@ -1,6 +1,6 @@
 // ==UserScript==
 // @name         XMOJ
-// @version      3.1.0
+// @version      3.1.1
 // @description  XMOJ增强脚本
 // @author       @XMOJ-Script-dev, @langningchen and the community
 // @namespace    https://github/langningchen
@@ -5202,7 +5202,7 @@ int main()
                                                     Delete.style.display = "";
                                                 }
                                             }
-                                            PostTitle.innerHTML = ResponseData.Data.Title + (ResponseData.Data.ProblemID == 0 ? "" : ` - 题目` + ` <a href="https://www.xmoj.tech/problem.php?id=` + ResponseData.Data.ProblemID + `">` + ResponseData.Data.ProblemID + `</a>`);
+                                            PostTitle.innerHTML = escapeHTML(ResponseData.Data.Title) + (ResponseData.Data.ProblemID == 0 ? "" : ` - 题目` + ` <a href="https://www.xmoj.tech/problem.php?id=` + ResponseData.Data.ProblemID + `">` + ResponseData.Data.ProblemID + `</a>`);
                                             document.title = "讨论" + ThreadID + ": " + ResponseData.Data.Title;
                                             PostAuthor.innerHTML = "<span></span>";
                                             GetUsernameHTML(PostAuthor.children[0], ResponseData.Data.UserID);
diff --git a/package.json b/package.json
index 3f59d6be..62b60c53 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "xmoj-script",
-  "version": "3.1.0",
+  "version": "3.1.1",
   "description": "an improvement script for xmoj.tech",
   "main": "AddonScript.js",
   "scripts": {