diff --git a/packages/hydrooj/package.json b/packages/hydrooj/package.json
index 156365f54..7b344ee5b 100644
--- a/packages/hydrooj/package.json
+++ b/packages/hydrooj/package.json
@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "2.15.12",
+    "version": "2.15.13",
     "bin": "bin/hydrooj.js",
     "main": "dist/loader.js",
     "typings": "dist/loader.d.ts",
diff --git a/packages/hydrooj/src/handler/problem.ts b/packages/hydrooj/src/handler/problem.ts
index 959f5bd3b..5a586c9f8 100644
--- a/packages/hydrooj/src/handler/problem.ts
+++ b/packages/hydrooj/src/handler/problem.ts
@@ -194,8 +194,13 @@ export class ProblemDetailHandler extends ProblemHandler {
     async get(..._args: any[]) {
         // Navigate to current additional file download
         // e.g. ![img](a.jpg) will navigate to ![img](./pid/file/a.jpg)
-        this.response.body.pdoc.content = this.response.body.pdoc.content
-            .replace(/\(file:\/\//g, `(./${this.pdoc.docId}/file/`);
+        if (typeof this.response.body.pdoc.content === 'string') {
+            this.response.body.pdoc.content = this.response.body.pdoc.content
+                .replace(/\(file:\/\//g, `(./${this.pdoc.docId}/file/`);
+        } else {
+            this.response.body.pdoc.content = JSON.parse(JSON.stringify(this.response.body.pdoc.content)
+                .replace(/\(file:\/\//g, `(./${this.pdoc.docId}/file/`));
+        }
     }
 
     @param('pid', Types.UnsignedInt)