CVE-2026-0999

Summary

Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate login method restrictions which allows an authenticated user to bypass SSO-only login requirements via userID-based authentication. Mattermost Advisory ID: MMSA-2025-00548

Affected Software

VendorProductVersion RangeStatus
MattermostMattermost11.1.0 <= 11.1.2affected
MattermostMattermost10.11.0 <= 10.11.9affected
MattermostMattermost11.2.0 <= 11.2.1affected
MattermostMattermost11.3.0unaffected
MattermostMattermost11.1.3unaffected
MattermostMattermost10.11.10unaffected
MattermostMattermost11.2.2unaffected

Weaknesses

  • CWE-303: CWE-303: Incorrect Implementation of Authentication Algorithm

ADP Enrichment

CISA ADP Vulnrichment

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

References