CVE-2025-8023
📋 TL;DR
This vulnerability allows system administrators in Mattermost to perform path traversal attacks by manipulating template file destination paths. Attackers can place malicious files outside intended directories, potentially compromising server integrity. Only Mattermost instances with vulnerable versions are affected.
💻 Affected Systems
- Mattermost Team Edition
- Mattermost Enterprise Edition
📦 What is this software?
Mattermost Server by Mattermost
Mattermost Server by Mattermost
Mattermost Server by Mattermost
Mattermost Server by Mattermost
⚠️ Risk & Real-World Impact
Worst Case
Malicious admin could place executable files in system directories, leading to remote code execution, data exfiltration, or complete server compromise.
Likely Case
Privileged attacker places malicious configuration or script files to gain persistence, escalate privileges, or disrupt service.
If Mitigated
With proper admin access controls and file system permissions, impact limited to unauthorized file placement within Mattermost directories.
🎯 Exploit Status
Exploitation requires admin access and knowledge of Mattermost template system. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 10.8.4, 10.5.9, 9.11.18, 10.9.3 or later
Vendor Advisory: https://mattermost.com/security-updates
Restart Required: No
Instructions:
1. Backup Mattermost configuration and database. 2. Download patched version from Mattermost downloads page. 3. Stop Mattermost service. 4. Replace binary/files with patched version. 5. Restart Mattermost service. 6. Verify version is updated.
🔧 Temporary Workarounds
Restrict Admin Access
allLimit system administrator accounts to trusted personnel only and implement principle of least privilege.
File System Restrictions
allConfigure Mattermost to run with minimal file system permissions and use chroot/jail where possible.
🧯 If You Can't Patch
- Implement strict access controls for admin accounts and monitor admin activity logs
- Use file integrity monitoring on Mattermost directories and system paths
🔍 How to Verify
Check if Vulnerable:
Check Mattermost version via System Console > About or run: mattermost versionCheck Version:
mattermost versionVerify Fix Applied:
Verify version is 10.8.4+, 10.5.9+, 9.11.18+, or 10.9.3+ using same commands📡 Detection & Monitoring
Log Indicators:
- Unusual template file operations
- Path traversal patterns in file paths
- Admin account performing unexpected file operations
Network Indicators:
- Unusual file upload patterns from admin accounts
SIEM Query:
source="mattermost" AND (event="file_upload" OR event="template_save") AND path="*../*"