CVE-2026-9162

Global session revocation does not invalidate active WebSocket connections

Published Jun 22, 2026 CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed

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

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Mattermost

unaffected

Version	Status	Constraints
`11.7.0`	affected	≤ 11.7.0
`11.6.0`	affected	≤ 11.6.2
`11.5.0`	affected	≤ 11.5.5
`10.11.0`	affected	≤ 10.11.17
`11.8.0`	unaffected	—
`11.7.1`	unaffected	—
`11.6.3`	unaffected	—
`11.5.6`	unaffected	—
`10.11.18`	unaffected	—

Configuration 1 [-]

OR	cpe:2.3:a:mattermost:mattermost_server::::::::
	cpe:2.3:a:mattermost:mattermost_server::::::::
	cpe:2.3:a:mattermost:mattermost_server::::::::
	cpe:2.3:a:mattermost:mattermost_server::::::::

No data.

Vendor Product Versions

Mattermost

Version	Status	Scheme	Platform
`[11.7.0,11.7.0]`	affected	semver	—
`[11.6.0,11.6.2]`	affected	semver	—
`[11.5.0,11.5.5]`	affected	semver	—
`[10.11.0,10.11.17]`	affected	semver	—
`11.8.0`	unaffected	semver	—
`11.7.1`	unaffected	semver	—
`11.6.3`	unaffected	semver	—
`11.5.6`	unaffected	semver	—
`10.11.18`	unaffected	semver	—

Remediation

Vendor Solution

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

Tracking

Advisories

Source	ID	Title
Github GHSA	GHSA-h998-hxxj-8q83	Mattermost doesn't invalidate cached authentication state for active WebSocket connections during global session revocation

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.334% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://mattermost.com/security-updates

History

Jun 22, 2026 4:30 PM First appearance in the feed. Affected vendors updated. Scoring metrics updated View changes

Type	Values Removed	Values Added
First Time appeared		Mattermost Mattermost mattermost
Vendors & Products		Mattermost Mattermost mattermost
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Jun 22, 2026 1:45 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
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
Title		Global session revocation does not invalidate active WebSocket connections
Weaknesses		CWE-613
References		https://mattermost.com/security-updates
Metrics		cvssV3_1 `{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'}`