CVE-2026-28759

4.3 Moyenne

Publiée le 18/05/2026 à 10:16 · Modifiée le 14/10/2026 à 22:10 · Analysée par le NVD · Source : responsibledisclosure@mattermost.com

Description

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

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Produits concernés

Mattermost
Mattermost mattermost server

Scores CVSS

Version	Score	Source	Vecteur
3.1	4.3 Moyenne	responsibledisclosure@mattermost.com	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N`

Faiblesses (CWE)

CWE-863

Références

https://mattermost.com/security-updates Vendor Advisory

Ailleurs

NVD
CVE.org
CIRCL Vulnerability-Lookup
CERT-FR
GitHub Advisories