CVE-2026-27659

Summary

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

Affected Software

VendorProductVersion RangeStatus
MattermostMattermost11.2.0 <= 11.2.2affected
MattermostMattermost10.11.0 <= 10.11.10affected
MattermostMattermost11.4.0 <= 11.4.0affected
MattermostMattermost11.3.0 <= 11.3.1affected
MattermostMattermost11.5.0unaffected
MattermostMattermost11.2.3unaffected
MattermostMattermost10.11.11unaffected
MattermostMattermost11.4.1unaffected
MattermostMattermost11.3.2unaffected

Weaknesses

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

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References