CVE-2025-52931
📋 TL;DR
The Mattermost Confluence Plugin before version 1.5.0 contains an improper input validation vulnerability that allows attackers to crash the plugin by sending malformed requests to the update channel subscription endpoint. This affects organizations using the vulnerable plugin version to integrate Mattermost with Confluence. The vulnerability can lead to denial of service for the plugin functionality.
💻 Affected Systems
- Mattermost Confluence Plugin
📦 What is this software?
Confluence by Mattermost
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service for Mattermost-Confluence integration, disrupting collaboration workflows and potentially affecting business operations that rely on this integration.
Likely Case
Temporary disruption of the Confluence plugin functionality in Mattermost, requiring plugin restart or server intervention to restore service.
If Mitigated
Minimal impact with proper rate limiting, input validation, and monitoring in place to detect and block malicious requests.
🎯 Exploit Status
Exploitation requires sending malformed requests to a specific endpoint. The vulnerability is in input handling logic, making exploitation straightforward once the endpoint is identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.5.0
Vendor Advisory: https://mattermost.com/security-updates
Restart Required: Yes
Instructions:
1. Access Mattermost System Console. 2. Navigate to Plugin Management. 3. Update Confluence Plugin to version 1.5.0 or later. 4. Restart the Mattermost server or plugin subsystem.
🔧 Temporary Workarounds
Disable Confluence Plugin
allTemporarily disable the vulnerable plugin until patching can be performed
/mmctl plugin disable com.mattermost.confluence
Implement WAF Rules
allAdd web application firewall rules to block malformed requests to the vulnerable endpoint
Add rule to block requests to '/plugins/com.mattermost.confluence/api/v1/channel-subscriptions/update' with malformed JSON body
🧯 If You Can't Patch
- Implement strict rate limiting on the vulnerable endpoint to prevent sustained attacks
- Deploy network monitoring to detect and alert on repeated malformed requests to the plugin endpoint
🔍 How to Verify
Check if Vulnerable:
Check the plugin version in Mattermost System Console > Plugin Management > Confluence PluginCheck Version:
/mmctl plugin list | grep confluenceVerify Fix Applied:
Verify plugin version shows 1.5.0 or later and test the update channel subscription endpoint with various request payloads📡 Detection & Monitoring
Log Indicators:
- Multiple 400/500 errors from '/plugins/com.mattermost.confluence/api/v1/channel-subscriptions/update' endpoint
- Plugin crash logs mentioning Confluence plugin
Network Indicators:
- High volume of POST requests to the vulnerable endpoint with malformed JSON
- Unusual traffic patterns to plugin endpoints
SIEM Query:
source="mattermost" AND (uri_path="/plugins/com.mattermost.confluence/api/v1/channel-subscriptions/update" AND status>=400) | stats count by src_ip