CVE-2025-0476
📋 TL;DR
Mattermost Mobile Apps versions up to 2.22.0 contain a vulnerability where specially crafted attachment names can cause the mobile app to crash when a user opens a channel containing such an attachment. This affects all users of vulnerable Mattermost mobile applications. The vulnerability allows denial of service against mobile app users.
💻 Affected Systems
- Mattermost Mobile App (iOS)
- Mattermost Mobile App (Android)
📦 What is this software?
Mattermost Mobile by Mattermost
⚠️ Risk & Real-World Impact
Worst Case
An attacker could repeatedly crash mobile apps for targeted users, disrupting communication and productivity across an organization's Mattermost deployment.
Likely Case
Temporary denial of service for mobile users who encounter malicious attachments, requiring app restart to restore functionality.
If Mitigated
Minimal impact with proper monitoring and rapid patching, as the vulnerability only affects mobile apps and doesn't compromise servers or data.
🎯 Exploit Status
Exploitation requires ability to post attachments to channels accessible by mobile users. No authentication bypass is involved.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: > 2.22.0
Vendor Advisory: https://mattermost.com/security-updates
Restart Required: Yes
Instructions:
1. Update Mattermost Mobile App from official app store (iOS App Store or Google Play Store). 2. Ensure all mobile users update to version > 2.22.0. 3. Restart the mobile app after update.
🔧 Temporary Workarounds
Disable mobile app usage
allTemporarily restrict mobile app access until patched
Attachment name filtering
allImplement server-side filtering of attachment names containing special characters
🧯 If You Can't Patch
- Educate users to avoid opening suspicious attachments in mobile app
- Monitor for unusual attachment uploads and investigate users posting attachments with unusual names
🔍 How to Verify
Check if Vulnerable:
Check mobile app version in app settings. If version is 2.22.0 or lower, the app is vulnerable.Check Version:
In Mattermost mobile app: Settings → About → VersionVerify Fix Applied:
Verify mobile app version is > 2.22.0 in app settings after update.📡 Detection & Monitoring
Log Indicators:
- Multiple mobile app crash reports from same users
- Unusual attachment upload patterns
Network Indicators:
- Increased mobile app reconnection attempts
SIEM Query:
Search for error logs containing 'crash' or 'attachment' from mobile user agents