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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 properly validate CSRF tokens in the /api/v4/access_control_policies/{policy_id}/activate endpoint, which allows an attacker to trick an admin into changing access control policy active status via a crafted request.. Mattermost Advisory ID: MMSA-2026-00578

PUBLISHED Reserved 2026-02-23 | Published 2026-03-25 | Updated 2026-03-25 | Assigner Mattermost




MEDIUM: 4.6CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

Problem types

CWE-352: Cross-Site Request Forgery (CSRF)

Product status

Default status
unaffected

11.2.0 (semver)
affected

10.11.0 (semver)
affected

11.4.0 (semver)
affected

11.3.0 (semver)
affected

11.5.0
unaffected

11.2.3
unaffected

10.11.11
unaffected

11.4.1
unaffected

11.3.2
unaffected

Credits

Joshua Rogers finder

References

mattermost.com/security-updates (MMSA-2026-00578) vendor-advisory

cve.org (CVE-2026-27659)

nvd.nist.gov (CVE-2026-27659)

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