CVE-2025-36530
📋 TL;DR
This vulnerability allows restricted admin users in Mattermost to install unauthorized custom plugins via path traversal during plugin imports. It bypasses plugin signature enforcement and marketplace restrictions, affecting Mattermost instances with restricted admin users who have plugin import permissions.
💻 Affected Systems
- Mattermost
📦 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 installs plugins with arbitrary code execution capabilities, leading to complete system compromise, data exfiltration, or lateral movement within the network.
Likely Case
Restricted admin installs unauthorized plugins that could leak sensitive data, disrupt service, or create backdoors for future attacks.
If Mitigated
Impact limited to plugin functionality disruption if proper access controls and monitoring are in place.
🎯 Exploit Status
Exploitation requires admin privileges with plugin import access and knowledge of path traversal techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to Mattermost 10.9.2, 10.8.4, 10.5.9, or 9.11.18
Vendor Advisory: https://mattermost.com/security-updates
Restart Required: No
Instructions:
1. Backup your Mattermost instance. 2. Download the patched version from Mattermost releases. 3. Follow Mattermost upgrade documentation for your deployment method. 4. Verify the upgrade completed successfully.
🔧 Temporary Workarounds
Restrict Plugin Import Permissions
allTemporarily remove plugin import capabilities from restricted admin roles until patching.
Use Mattermost System Console > User Management > Permissions to modify role permissions
🧯 If You Can't Patch
- Implement strict access controls to limit plugin import functionality to only necessary administrators.
- Enable detailed logging and monitoring of plugin installation activities for anomaly detection.
🔍 How to Verify
Check if Vulnerable:
Check Mattermost version via System Console > About Mattermost or run: mattermost versionCheck Version:
mattermost versionVerify Fix Applied:
Confirm version is updated to 10.9.2, 10.8.4, 10.5.9, or 9.11.18 using the same version check.📡 Detection & Monitoring
Log Indicators:
- Unusual plugin installation events from restricted admin users
- Failed plugin signature validation attempts
- Path traversal patterns in plugin import logs
Network Indicators:
- Unexpected outbound connections after plugin installations
- Unusual traffic patterns to/from Mattermost plugin directories
SIEM Query:
source="mattermost" AND (event="plugin_install" OR event="plugin_import") AND user_role="restricted_admin"