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

INFO

Published Date :

2026-03-26T10:43:24.611Z

Last Modified :

2026-03-26T13:58:41.567Z

Source :

Mattermost
AFFECTED PRODUCTS

The following products are affected by CVE-2026-4274 vulnerability.

Vendors Products
Mattermost
  • Mattermost
  • Mattermost Server
REFERENCES

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-4274.

URL Resource
https://mattermost.com/security-updates cve-icon cve-icon
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