CVE-2026-9162Medium· 4.3▾ SunlitMattermost doesn't invalidate cached authentication state for active WebSocket connections during global session revocation
▾ Sunlit zone — Low / medium · no exploitation signal
impact 23.7 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Sep 15.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
0.3%
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
github.com/mattermost/mattermost-server >= 11.7.0, < 11.7.1github.com/mattermost/mattermost-server >= 11.6.0, < 11.6.3github.com/mattermost/mattermost-server >= 11.5.0, < 11.5.6github.com/mattermost/mattermost-server >= 10.11.0, < 10.11.18Upgrade to a patched release:
github.com/mattermost/mattermost-server 11.7.1github.com/mattermost/mattermost-server 11.6.3github.com/mattermost/mattermost-server 11.5.6github.com/mattermost/mattermost-server 10.11.18Connected by shared product, vendor, weakness, or advisory.
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