CVE-2026-9162
MEDIUM 4.3Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to invalidate cached authentication state for active WebSocket connections during global session revocation, which allows a user with an existing WebSocket connection to remain authenticated and continue receiving real-time events until the cached session expires or the client reconnects.. Mattermost Advisory ID: MMSA-2026-00664
NO EXPLOITATION SIGNALS
No known exploitation, public exploit, or elevated probability at this time. Track for changes.
Exploitation likelihood
0.2%chance of exploitation in 30 days · 10th percentile
○ In CISA KEV
○ Public exploit / PoC
Impact if exploited
4.3CVSS 3.1 · MEDIUM
- ConfidentialityLow
- IntegrityNone
- AvailabilityNone
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Weakness (CWE)
- CWE-613
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N