CVE-2025-3611: Improper Access Control in Mattermost allows System Managers to view team details despite role restrictions

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-30 · updated 2026-06-17
Weakness: CWE-863

Description

Mattermost versions 10.7.x <= 10.7.0, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fails to properly enforce access control restrictions for System Manager roles, allowing authenticated users with System Manager privileges to view team details they should not have access to via direct API requests to team endpoints, even when explicitly configured with 'No access' to Teams in the System Console.

Affected products

Mattermost: from 9.11.0 before 9.11.13; from 10.5.0 before 10.5.4; 10.7.0, 10.7.0-rc1, 10.7.0-rc2 — fixed in 10.5.4, 9.11.13

How to fix

Upgrade to a fixed version: Mattermost 10.5.4, 9.11.13. Check the vendor advisory for mitigations.

References

https://mattermost.com/security-updates

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