CVE-2026-9162 PUBLISHED

Global session revocation does not invalidate active WebSocket connections

Assigner: Mattermost
Reserved: 21.05.2026 Published: 22.06.2026 Updated: 22.06.2026

Mattermost 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

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CVSS Score: 4.3

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	Low
Privileges Required	Low	Integrity Impact	None
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	Mattermost
Product	Mattermost
Versions	Default: unaffected affected from 11.7.0 to 11.7.0 (incl.) affected from 11.6.0 to 11.6.2 (incl.) affected from 11.5.0 to 11.5.5 (incl.) affected from 10.11.0 to 10.11.17 (incl.) Version 11.8.0 is unaffected Version 11.7.1 is unaffected Version 11.6.3 is unaffected Version 11.5.6 is unaffected Version 10.11.18 is unaffected

Solutions

Update Mattermost to versions 11.8.0, 11.7.1, 11.6.3, 11.5.6, 10.11.18 or higher.

Credits

winfunc finder

References

MMSA-2026-00664

Problem Types

CWE-613: Insufficient Session Expiration CWE