CVE-2026-3473 (GCVE-0-2026-3473)

Vulnerability from cvelistv5 – Published: 2026-05-22 10:27 – Updated: 2026-05-22 12:12
VLAI
Title
Improper file ownership validation in the Boards API allows unauthorised file access
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate file ownership and access control, which allows an authenticated user to access and download files belonging to other users or teams via crafted Boards API requests using valid file IDs.. Mattermost Advisory ID: MMSA-2026-00620
Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-639 - Authorization Bypass Through User-Controlled Key
Assigner
References
URL Tags
https://mattermost.com/security-updates vendor-advisory
Impacted products
Vendor Product Version
Mattermost Mattermost Affected: 11.6.0 , ≤ 11.6.0 (semver)
Affected: 11.5.0 , ≤ 11.5.3 (semver)
Affected: 11.4.0 , ≤ 11.4.4 (semver)
Affected: 10.11.0 , ≤ 10.11.14 (semver)
Unaffected: 11.7.0
Unaffected: 11.6.1
Unaffected: 11.5.4
Unaffected: 11.4.5
Unaffected: 10.11.15
Create a notification for this product.
Credits
eahmed
Show details on NVD website
To clipboard 

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  • 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.
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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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