CVE-2025-13321
📋 TL;DR
Mattermost Desktop App versions before 6.0.0 fail to properly clear sensitive information from logs and data when servers are deleted. This allows attackers with local system access to read potentially sensitive information from application logs. All users running vulnerable desktop app versions are affected.
💻 Affected Systems
- Mattermost Desktop App
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers with local access could extract authentication tokens, messages, or other sensitive data from logs, potentially enabling account compromise or data exfiltration.
Likely Case
Local attackers or malware could harvest session tokens or sensitive information from logs, leading to unauthorized access to Mattermost accounts.
If Mitigated
With proper access controls and logging disabled, impact is limited to local file system access only.
🎯 Exploit Status
Exploitation requires local file system access to read application logs.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.0.0 or later
Vendor Advisory: https://mattermost.com/security-updates
Restart Required: Yes
Instructions:
1. Download Mattermost Desktop App version 6.0.0 or later from official sources. 2. Install the update. 3. Restart the application.
🔧 Temporary Workarounds
Disable Detailed Logging
allConfigure Mattermost to use minimal or no logging to reduce sensitive data exposure.
Check Mattermost settings for logging options and set to minimal or disabled
Secure Log Files
allSet restrictive file permissions on Mattermost log directories.
chmod 600 ~/.config/Mattermost/logs/* (Linux/macOS)
Set ACLs to restrict access to Mattermost logs folder (Windows)
🧯 If You Can't Patch
- Implement strict access controls on user workstations to prevent unauthorized local access
- Regularly clear Mattermost log files and implement log rotation with secure deletion
🔍 How to Verify
Check if Vulnerable:
Check Mattermost Desktop App version in Help > About menu. If version is below 6.0.0, system is vulnerable.Check Version:
Check Help > About in Mattermost Desktop App interfaceVerify Fix Applied:
After updating, verify version is 6.0.0 or higher in Help > About menu. Test by deleting a server and checking logs for sensitive data.📡 Detection & Monitoring
Log Indicators:
- Unauthorized access to Mattermost log files
- Sensitive data patterns in log files
Network Indicators:
- None - this is a local file system vulnerability
SIEM Query:
File access events to Mattermost log directories from unauthorized users or processes