CVE-2026-3115 — Guest users can view group member IDs without respecting view restrictions

CVE-2026-3115

Guest users can view group member IDs without respecting view restrictions PUBLISHED

Description (CNA)

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 (CNA)

Vendor / product	Versions
Mattermost / Mattermost	affected 11.2.0 through 11.2.2; affected 10.11.0 through 10.11.10; affected 11.4.0 through 11.4.0; affected 11.3.0 through 11.3.1; unaffected 11.5.0; unaffected 11.2.3; unaffected 10.11.11; unaffected 11.4.1; unaffected 11.3.2

CWE

CWE-863

References

https://mattermost.com/security-updates

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.