CVE-2026-28759mediumCWE-863

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

13Vexday Risk Score

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

ssvc Trackcvss 4.3epss 0.2%

probabilidade de exploração

0.2%top 95% das CVEs

exploração observada

nãonenhuma fonte 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

Produtos afetados

Mattermost · Mattermost

Referências

https://mattermost.com/security-updates