CVE-2021-25769
📋 TL;DR
This vulnerability in JetBrains YouTrack prevents administrators from accessing attachments stored in the system. It affects YouTrack administrators who need to review or manage user-uploaded files. The issue existed in versions before 2020.4.6808.
💻 Affected Systems
- JetBrains YouTrack
📦 What is this software?
Youtrack by Jetbrains
⚠️ Risk & Real-World Impact
Worst Case
Administrators cannot access critical evidence or documentation needed for investigations, compliance audits, or user support cases, potentially leading to regulatory violations or unresolved security incidents.
Likely Case
Administrators experience workflow disruption when trying to access user-submitted attachments for troubleshooting, moderation, or administrative review.
If Mitigated
Administrators use alternative methods to access attachment content or rely on users to resubmit files through other channels.
🎯 Exploit Status
This is an availability issue rather than a traditional security exploit; administrators simply cannot access attachments through the normal interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2020.4.6808 and later
Vendor Advisory: https://blog.jetbrains.com/blog/2021/02/03/jetbrains-security-bulletin-q4-2020/
Restart Required: Yes
Instructions:
1. Backup your YouTrack instance and database. 2. Download YouTrack 2020.4.6808 or later from the JetBrains website. 3. Follow the YouTrack upgrade documentation for your deployment method (Docker, standalone, etc.). 4. Restart the YouTrack service after upgrade.
🔧 Temporary Workarounds
Direct database access for attachments
allAccess attachments directly from the YouTrack database or file storage if configured for external storage
User-assisted access
allHave users download and resend attachments through alternative channels when administrative review is needed
🧯 If You Can't Patch
- Implement strict access controls and monitoring for direct database/file system access to attachments
- Establish alternative procedures for evidence collection and compliance documentation that don't rely on YouTrack attachment access
🔍 How to Verify
Check if Vulnerable:
Check YouTrack version in Administration → Global Settings → About. If version is below 2020.4.6808, the system is vulnerable.Check Version:
Check the About page in YouTrack web interface or examine the YouTrack server logs for version informationVerify Fix Applied:
After upgrading to 2020.4.6808 or later, verify administrators can successfully access attachments through the YouTrack interface.📡 Detection & Monitoring
Log Indicators:
- Administrator login attempts followed by attachment access failures in YouTrack logs
- Error messages related to attachment access permissions in server logs
Network Indicators:
- Increased administrator requests to attachment endpoints with subsequent error responses
SIEM Query:
source="youtrack" AND ("attachment" AND ("access denied" OR "permission" OR "not found")) AND user_role="admin"