CVE-2026-3115

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 apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594

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-863: CWE-863: Incorrect Authorization

ADP Enrichment

CISA ADP Vulnrichment

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

References