CVE-2026-4274mediumCWE-863

CVE-2026-4274: falha de média gravidade em Mattermost

Insufficient authorization in shared channel membership sync grants team-level access instead of channel-level access

Publicada em

Seguir esta CVE+ Monitorar Mattermost+ Monitorar github.com/mattermost/mattermost-server

Aviso por e-mail quando ela entrar no KEV, ganhar PoC pública ou subir de nota.

13Vexday Risk Score

Sem sinal de exploração. Nenhum artefato público de exploração conhecido até agora.

ssvc Trackcvss 5.4epss 0.1%
Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to restrict team-level access when processing membership sync from a remote cluster, which allows a malicious remote cluster to grant a user access to an entire private team instead of only the shared channel via sending crafted membership sync messages that trigger team membership assignment. Mattermost Advisory ID: MMSA-2026-00574
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Produtos afetados
Mattermost · Mattermost
CVEs relacionadas — Mattermost

No mesmo produto, das mais perigosas para as menos.

CVE-2025-25279CRITICALArbitrary file read in Mattermost Boards via import & export board archiveEPSS 24.2%CVE-2021-37859HIGHReflected XSS in OAuth FlowEPSS 3.3%CVE-2022-3257LOWServer-side Denial of Service while processing a specifically crafted GIF fileEPSS 1.3%CVE-2022-4044MEDIUMAuthenticated user could send multiple requests containing a large Auto Responder Message payload and can crash a Mattermost serverEPSS 1.1%CVE-2022-3147LOWServer-side Denial of Service while processing a specifically crafted JPEG fileEPSS 1.1%CVE-2025-4981CRITICALPath Traversal Leading to RCE by Any Authenticated Mattermost UserEPSS 1.0%