diff --git a/packages/hydrooj/src/model/problem.ts b/packages/hydrooj/src/model/problem.ts
index 5ff38a5a9..6f1e48f62 100644
--- a/packages/hydrooj/src/model/problem.ts
+++ b/packages/hydrooj/src/model/problem.ts
@@ -330,8 +330,7 @@ export class ProblemModel {
     }
 
     static async getPrefixList(domainId: string, prefix: string) {
-        prefix = prefix.toLowerCase();
-        const $regex = new RegExp(`\\A${escapeRegExp(prefix)}`, 'gmi');
+        const $regex = new RegExp(`^${escapeRegExp(prefix.toLowerCase())}`, 'i');
         const filter = { $or: [{ pid: { $regex } }, { title: { $regex } }] };
         return await document.getMulti(domainId, document.TYPE_PROBLEM, filter, ['domainId', 'docId', 'pid', 'title'])
             .limit(20).toArray();
diff --git a/packages/hydrooj/src/model/storage.ts b/packages/hydrooj/src/model/storage.ts
index 9e87b6487..49b32a50f 100644
--- a/packages/hydrooj/src/model/storage.ts
+++ b/packages/hydrooj/src/model/storage.ts
@@ -60,7 +60,7 @@ export class StorageModel {
         if (target.includes('..') || target.includes('//')) throw new Error('Invalid path');
         if (target.length && !target.endsWith('/')) target += '/';
         const results = await StorageModel.coll.find({
-            path: { $regex: new RegExp(`^${escapeRegExp(target)}${recursive ? '' : '[^/]+$'}`, 'i') },
+            path: { $regex: `^${escapeRegExp(target)}${recursive ? '' : '[^/]+$'}` },
             autoDelete: null,
         }).toArray();
         return results.map((i) => ({
diff --git a/packages/hydrooj/src/model/user.ts b/packages/hydrooj/src/model/user.ts
index 05457bfba..5df7d011a 100644
--- a/packages/hydrooj/src/model/user.ts
+++ b/packages/hydrooj/src/model/user.ts
@@ -367,8 +367,7 @@ class UserModel {
 
     @ArgMethod
     static async getPrefixList(domainId: string, prefix: string, limit: number = 50) {
-        prefix = prefix.toLowerCase();
-        const $regex = new RegExp(`\\A${escapeRegExp(prefix)}`, 'gmi');
+        const $regex = `^${escapeRegExp(prefix.toLowerCase())}`;
         const udocs = await coll.find({ unameLower: { $regex } })
             .limit(limit).project({ _id: 1 }).toArray();
         const users = [];