CVE-2026-9162 | Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5… | CVSS 4.3 MEDIUM

Description

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

Metadata

CVE ID: CVE-2026-9162
State: PUBLISHED
Assigner: Mattermost
Reserved: 2026-05-21 11:17 UTC
Published: 2026-06-22 13:36 UTC
Last updated: 2026-06-22 15:40 UTC
Primary CWE: CWE-613
CWE-613: Insufficient Session Expiration
Vendor / Product: Mattermost / Mattermost
Sources: cve.org · NVD

Severity & Metrics

4.3 MEDIUM CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
Mattermost	Mattermost	—	11.7.0 ≤ 11.7.0, 11.6.0 ≤ 11.6.2, 11.5.0 ≤ 11.5.5, 10.11.0 ≤ 10.11.17 …

Weakness (CWE)

CWE	Source	Description
CWE-613	cna	CWE-613: Insufficient Session Expiration

CVSS scores (1)

Score	Severity	Version	Source	Vector
4.3	MEDIUM	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

References (1)

MMSA-2026-00664 https://mattermost.com/security-updates