CVE-2025-64641
📋 TL;DR
This vulnerability allows malicious Mattermost users to create posts with fake Jira plugin actions that exfiltrate Jira tickets when other users interact with them. It affects Mattermost instances with Jira integration where users can create posts. The risk is limited to authenticated users who can create posts in channels.
💻 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
Sensitive Jira tickets containing confidential information, security details, or customer data could be exfiltrated to unauthorized parties through malicious posts.
Likely Case
Limited exposure of internal Jira tickets to unauthorized Mattermost users within the same organization, potentially revealing project details, bug reports, or internal discussions.
If Mitigated
If proper access controls and monitoring are in place, impact is limited to low-severity information disclosure within the organization's internal collaboration platform.
🎯 Exploit Status
Exploitation requires authenticated access to Mattermost with post creation privileges. The attack involves creating malicious posts that mimic legitimate Jira plugin actions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to Mattermost 11.1.1, 11.0.6, 10.12.4, or 10.11.8
Vendor Advisory: https://mattermost.com/security-updates
Restart Required: Yes
Instructions:
1. Backup your Mattermost instance. 2. Download the patched version from official Mattermost channels. 3. Stop the Mattermost service. 4. Install the updated version. 5. Restart the Mattermost service. 6. Verify the update was successful.
🔧 Temporary Workarounds
Disable Jira Plugin
allTemporarily disable the Jira plugin to prevent exploitation while planning the update.
mmctl plugin disable com.mattermost.plugin-jira
Restrict Post Creation Permissions
allTighten permissions so only trusted users can create posts with actions.
🧯 If You Can't Patch
- Implement strict monitoring for unusual post creation patterns and Jira ticket access
- Educate users to avoid interacting with suspicious posts containing Jira-related actions
🔍 How to Verify
Check if Vulnerable:
Check your Mattermost version against affected versions. If using affected version with Jira plugin enabled, you are vulnerable.Check Version:
mmctl versionVerify Fix Applied:
After updating, verify the version shows as patched and test that Jira plugin actions properly validate origin.📡 Detection & Monitoring
Log Indicators:
- Unusual frequency of /share-issue-publicly actions
- Posts with Jira actions from non-Jira plugin sources
- Failed Jira API calls from unexpected sources
Network Indicators:
- Unexpected Jira API calls from Mattermost instances
- Traffic patterns showing Jira data being accessed via non-standard paths
SIEM Query:
source="mattermost" AND (action="/share-issue-publicly" OR plugin="jira") | stats count by user, channel