CVE-2026-3590

Summary

Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated sessions via concurrent requests.. Mattermost Advisory ID: MMSA-2026-00624

Affected Software

VendorProductVersion RangeStatus
MattermostMattermost10.11.0 <= 10.11.12affected
MattermostMattermost11.5.0 <= 11.5.0affected
MattermostMattermost11.4.0 <= 11.4.2affected
MattermostMattermost11.3.0 <= 11.3.2affected
MattermostMattermost11.6.0unaffected
MattermostMattermost10.11.13unaffected
MattermostMattermost11.5.1unaffected
MattermostMattermost11.4.3unaffected
MattermostMattermost11.3.3unaffected

Weaknesses

  • CWE-367: CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References