5.4

CVE-2026-4274

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

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
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Mattermost ≫ Mattermost Server Version >= 10.11.0 < 10.11.11
Mattermost ≫ Mattermost Server Version >= 11.2.0 < 11.2.3
Mattermost ≫ Mattermost Server Version >= 11.3.0 < 11.3.2
Mattermost ≫ Mattermost Server Version >= 11.4.0 < 11.4.1
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.03% 0.1
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
responsibledisclosure@mattermost.com 5.4 2.8 2.5
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
CWE-863 Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.