Continued event access via cached WebSocket authentication
Published Jun 22, 2026 · Updated Jun 22, 2026
Insufficient session expiration in affected Mattermost 10.11 and 11.x releases allows remote authenticated users to keep receiving events. Global session revocation leaves authentication state cached for an active WebSocket, so the connection remains authorized until cache expiry or reconnection. Exploitation requires a WebSocket established before revocation; exposure is limited to real-time events available to the revoked session.
Summary
What happened
Insufficient session expiration in affected Mattermost 10.11 and 11.x releases allows remote authenticated users to keep receiving events. Global session revocation leaves authentication state cached for an active WebSocket, so the connection remains authorized until cache expiry or reconnection. Exploitation requires a WebSocket established before revocation; exposure is limited to real-time events available to the revoked session.
The record
- CVE
- CVE-2026-9162
- Published
- Jun 22, 2026
- Updated
- Jun 22, 2026
- Vendor
- Mattermost
- Product
- Mattermost
- Classifications
- CWE-613, T1078
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 22, 2026CVE publishedPublication date reported by the CVE source.
- Jun 22, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.11.0 <=10.11.17
- Affected versionversion=11.5.0 <=11.5.5
- Affected versionversion=11.6.0 <=11.6.2
- Affected versionversion=11.7.0 <=11.7.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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