CVE-2026-28759mediumCWE-863

Insufficient authorization in shared channel membership sync allows remote cluster to remove users from arbitrary channels

13Vexday Risk Score

Sin señal de explotación. Ningún artefacto público de explotación conocido hasta ahora.

ssvc Trackcvss 4.3epss 0.2%

probabilidad de explotación

0.2%top 95% de las CVE

explotación observada

noninguna fuente lo reporta

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate that a remote cluster has access to a channel before processing membership removal requests during shared channel membership sync, which allows a malicious remote cluster to remove any user from any channel, including private channels, via crafted membership sync messages targeting channels the remote cluster is not authorized to access. Mattermost Advisory ID: MMSA-2026-00576

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

Productos afectados

Mattermost · Mattermost

Referencias

https://mattermost.com/security-updates