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CVE-2026-4274

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CVSS 3.1
5.4 medium
EPSS
<1%p4
Published
()
Modified
Description

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

Vendors
mattermost
Products
mattermost server
Weakness
CWE-863
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
NVD CVE.org GitHub PoCs EPSS (0.1%)

In the news

No ingested article mentions this CVE yet.