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CVE-2026-20796 (GCVE-0-2026-20796)

Vulnerability from cvelistv5 – Published: 2026-02-13 10:30 – Updated: 2026-02-13 17:02
VLAI
Title
Time-of-check time-of-use vulnerability in common teams API
Summary
Mattermost versions 10.11.x <= 10.11.9 fail to properly validate channel membership at the time of data retrieval which allows a deactivated user to learn team names they should not have access to via a race condition in the /common_teams API endpoint.. Mattermost Advisory ID: MMSA-2025-00549
Severity
3.1 (Low)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-02-13 17:01 UTC
CWE
  • CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition
Assigner
References
URL Tags
https://mattermost.com/security-updates vendor-advisory
Impacted products
Vendor Product Version CPE status
Mattermost Mattermost Affected: 10.11.0 , ≤ 10.11.9 (semver)
Unaffected: 11.3.0
Unaffected: 10.11.10
guessed Create a notification for this product.
Credits
Juho Forsén
Show details on NVD website
To clipboard 

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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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