CVE-2025-65796
📋 TL;DR
CVE-2025-65796 is an improper access control vulnerability in usememos memos v0.25.2 that allows authenticated users with low-level privileges to delete reactions (likes, comments, etc.) on other users' memos. This affects all deployments running the vulnerable version of the memos note-taking software. The vulnerability undermines data integrity and user trust in the platform.
💻 Affected Systems
- usememos/memos
📦 What is this software?
Memos by Usememos
⚠️ Risk & Real-World Impact
Worst Case
Malicious insiders or compromised low-privilege accounts could systematically delete reactions across the platform, causing data loss, disrupting user engagement metrics, and potentially enabling harassment campaigns by removing positive feedback from targeted users.
Likely Case
Disgruntled users or curious low-privilege accounts delete reactions on memos they shouldn't have access to, causing minor data integrity issues and user complaints about missing likes or comments.
If Mitigated
With proper access controls and monitoring, impact is limited to isolated incidents that can be quickly detected and rolled back through database backups.
🎯 Exploit Status
Exploitation requires authenticated access with any user account. The vulnerability is in the API endpoint authorization logic for reaction deletion.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v0.25.3 or later
Vendor Advisory: https://github.com/usememos/memos/pull/5217
Restart Required: Yes
Instructions:
1. Backup your memos database. 2. Stop the memos service. 3. Update to v0.25.3 or later using your deployment method (Docker, binary, package manager). 4. Restart the memos service. 5. Verify the update was successful.
🔧 Temporary Workarounds
Temporary API restriction
allImplement web application firewall rules or reverse proxy configuration to restrict access to reaction deletion endpoints for low-privilege users.
# Example nginx location block to restrict DELETE /api/v1/memos/:memoId/reactions/:reactionId
location ~ ^/api/v1/memos/\d+/reactions/\d+$ {
if ($request_method = DELETE) {
return 403;
}
}
🧯 If You Can't Patch
- Implement strict user permission auditing and monitoring for reaction deletion events.
- Enable detailed logging of all API calls to reaction endpoints and set up alerts for suspicious patterns.
🔍 How to Verify
Check if Vulnerable:
Check if your memos version is exactly v0.25.2 by visiting /api/v1/status endpoint or checking the application version in the UI.Check Version:
curl -s http://your-memos-instance/api/v1/status | grep -o '"version":"[^"]*"'Verify Fix Applied:
After updating, test with a low-privilege account attempting to delete a reaction on another user's memo - this should now be properly rejected with a 403 error.📡 Detection & Monitoring
Log Indicators:
- Multiple DELETE requests to /api/v1/memos/*/reactions/* from low-privilege user accounts
- 403 errors followed by successful 200 responses on reaction deletion endpoints
Network Indicators:
- Unusual patterns of DELETE requests to reaction endpoints outside normal user behavior
SIEM Query:
source="memos.log" AND (uri_path="/api/v1/memos/*/reactions/*" AND http_method="DELETE") AND user_role="USER" | stats count by src_user