CVE-2026-91181

Summary

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 Fail to sanitize Team objects returned by the data retention teams endpoint which allows an authenticated user holding only the read-only Data Retention Policy permission to obtain a private team's secret invite_id and email, and use it to join the team without authorization, via GET /api/v4/data_retention/policies/{policy_id}/teams.. Mattermost Advisory ID: MMSA-2026-00702

Affected Software

VendorProductVersion RangeStatus
MattermostMattermost11.9.0 <= 11.9.0affected
MattermostMattermost11.8.0 <= 11.8.4affected
MattermostMattermost11.7.0 <= 11.7.7affected
MattermostMattermost10.11.0 <= 10.11.22affected
MattermostMattermost11.10.0unaffected
MattermostMattermost11.9.1unaffected
MattermostMattermost11.8.5unaffected
MattermostMattermost11.7.8unaffected
MattermostMattermost10.11.23unaffected

Weaknesses

  • CWE-863: CWE-863: Incorrect Authorization

References