CVE-2025-62175
📋 TL;DR
Mastodon servers running vulnerable versions allow disabled or suspended user accounts to maintain real-time streaming API connections, receiving updates despite being blocked from other interactions. This undermines administrative moderation actions by permitting continued access to streaming data. Only Mastodon instances with affected versions are impacted.
💻 Affected Systems
- Mastodon
📦 What is this software?
Mastodon by Joinmastodon
Mastodon by Joinmastodon
Mastodon by Joinmastodon
⚠️ Risk & Real-World Impact
Worst Case
Suspended malicious users continue monitoring real-time activity, potentially gathering intelligence or coordinating with active accounts despite moderation actions.
Likely Case
Suspended users maintain passive access to streaming updates, reducing effectiveness of account suspension as a moderation tool.
If Mitigated
With proper patching, suspended accounts are fully disconnected from all API endpoints including streaming.
🎯 Exploit Status
Exploitation requires a user account that gets suspended while maintaining an active streaming connection. No authentication bypass is needed beyond the initial account access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.4.6, 4.3.14, or 4.2.27
Vendor Advisory: https://github.com/mastodon/mastodon/security/advisories/GHSA-r2fh-jr9c-9pxh
Restart Required: No
Instructions:
1. Identify your Mastodon version. 2. Upgrade to the appropriate patched version: 4.4.6 for 4.4.x, 4.3.14 for 4.3.x, or 4.2.27 for 4.2.x. 3. Follow standard Mastodon upgrade procedures from official documentation.
🔧 Temporary Workarounds
No workarounds available
allThe vendor advisory states no known workarounds exist for this vulnerability.
🧯 If You Can't Patch
- Monitor for streaming connections from suspended accounts and manually terminate them
- Consider temporarily disabling streaming API functionality if patching is not possible
🔍 How to Verify
Check if Vulnerable:
Check Mastodon version against affected versions: anything before 4.4.6, 4.3.14, or 4.2.27Check Version:
Check Mastodon admin interface or run: RAILS_ENV=production bundle exec rails about | grep 'Mastodon'Verify Fix Applied:
Confirm version is 4.4.6, 4.3.14, or 4.2.27 or later, then test that suspended accounts cannot maintain streaming connections📡 Detection & Monitoring
Log Indicators:
- Streaming API connections persisting after account suspension
- WebSocket connections from suspended user accounts
Network Indicators:
- Persistent WebSocket connections from IPs associated with suspended accounts
SIEM Query:
source="mastodon" ("suspended" OR "disabled") AND ("streaming" OR "websocket") AND NOT "disconnected"