Mattermost
CVE-2026-1629
MEDIUM
Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Lifecycle Timeline
2DescriptionCVE.org
Mattermost versions 10.11.x <= 10.11.10 Fail to invalidate cached permalink preview data when a user loses channel access which allows the user to continue viewing private channel content via previously cached permalink previews until cache reset or relogin.. Mattermost Advisory ID: MMSA-2026-00580
AnalysisAI
Mattermost 10.11.x through 10.11.10 fails to clear cached permalink preview data when a user's channel access is revoked, allowing authenticated users to view private channel content through previously cached previews until the cache expires or they re-login. An authenticated attacker who previously had access to a private channel can exploit this to maintain visibility into sensitive channel communications after access removal. A patch is not currently available for this medium-severity vulnerability.
Technical ContextAI
This vulnerability is classified as Operation on a Resource after Expiration or Release (CWE-672).
RemediationAI
Monitor vendor advisories for patches. Apply mitigations such as network segmentation, access restrictions, and monitoring.
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External POC / Exploit Code
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