CVE-2026-9597

Summary

Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4 fail to verify whether a guest account is deactivated before creating a session in the magic-link token login path, which allows a deactivated guest user to obtain a fully functional session via a magic-link token issued prior to deactivation.. Mattermost Advisory ID: MMSA-2026-00681

Affected Software

VendorProductVersion RangeStatus
MattermostMattermost11.7.0 <= 11.7.2affected
MattermostMattermost11.6.0 <= 11.6.4affected
MattermostMattermost11.8.0unaffected
MattermostMattermost11.7.3unaffected
MattermostMattermost11.6.5unaffected

Weaknesses

  • CWE-305: CWE-305 – Authentication Bypass by Primary Weakness

ADP Enrichment

CISA ADP Vulnrichment

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

References