CVE-2026-9162
Global session revocation does not invalidate active WebSocket connections
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
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Global session revocation does not invalidate active WebSocket connections
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
- Record
CVE-2026-9162- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-613
- Updated
- 2026-11-02
EUVDEUVD-2026-38247
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
- Record
EUVD-2026-38247- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-h998-hxxj-8q83
Mattermost doesn't invalidate cached authentication state for active WebSocket connections during global session revocation
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
- Record
GHSA-h998-hxxj-8q83- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-613
- Updated
- 2026-11-02
NVD
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
- Record
CVE-2026-9162- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-613
- Updated
- 2026-11-02
OSV
Global session revocation does not invalidate active WebSocket connections
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
- Record
CVE-2026-9162- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-613
- Updated
- 2026-11-07
OSVGHSA-h998-hxxj-8q83
Mattermost doesn't invalidate cached authentication state for active WebSocket connections during global session revocation
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
- Record
GHSA-h998-hxxj-8q83- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-613
- Updated
- 2026-11-02
OSVGO-2026-6482 No score
Mattermost doesn't invalidate cached authentication state for active WebSocket connections during global session revocation in github.com/mattermost/mattermost-server
Mattermost doesn't invalidate cached authentication state for active WebSocket connections during global session revocation in github.com/mattermost/mattermost-server
- Record
GO-2026-6482- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/mattermost/mattermost-serverGo |
11.7.0 up to 11.7.1 | 11.7.1 |
github.com/mattermost/mattermost-serverGo |
11.6.0 up to 11.6.3 | 11.6.3 |
github.com/mattermost/mattermost-serverGo |
11.5.0 up to 11.5.6 | 11.5.6 |
github.com/mattermost/mattermost-serverGo |
10.11.0 up to 10.11.18 | 10.11.18 |
github.com/mattermost/mattermost-serverGo |
10.11.0+incompatible up to 10.11.18+incompatible, 11.5.0+incompatible up to 11.5.6+incompatible, 11.6.0+incompatible up to 11.6.3+incompatible, 11.7.0+incompatible up to 11.7.1+incompatible | 10.11.18+incompatible11.5.6+incompatible11.6.3+incompatible11.7.1+incompatible |
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-9162 is a medium vulnerability (CVSS 4.3) in Mattermost, published June 22, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.33%, the 26th percentile. Fixed in github.com/mattermost/mattermost-server 11.7.1.