CVE-2026-3473

Improper file ownership validation in the Boards API allows unauthorised file access

CVSS 5.9 MEDIUMEPSS 0.1%CWE-639

Vexday Risk Score

13Bajo

Decisión SSVC (CISA)

Track

Sin señal de explotación → monitorear

CVSS 5.9EPSS 0.1%KEV nãoPoC —Nuclei —Metasploit —Patch referenciado

Ciclo de vida

22 may 2026Publicada en NVD

Recomendación: Monitorear — sin señal de explotación por ahora.

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

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N

Productos afectados

Mattermost · Mattermost

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Referencias

https://mattermost.com/security-updates