CVE-2026-16047 — Board channel linking without read channel permission validation

CVE-2026-16047

Board channel linking without read channel permission validation PUBLISHED

Description (CNA)

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fail to validate that users have read access to a channel before linking a board to it, which allows an authenticated attacker to discover the membership of private channels on the same team via creating, patching, importing, or bulk-creating boards with an arbitrary channelId. Mattermost Advisory ID: MMSA-2026-00674

Affected (CNA)

Vendor / product	Versions
Mattermost / Mattermost	affected 11.7.0 through 11.7.6; affected 10.11.0 through 10.11.21; affected 11.8.0 through 11.8.3; unaffected 11.9.0; unaffected 11.7.7; unaffected 10.11.22; unaffected 11.8.4

CWE

CWE-862

References

https://mattermost.com/security-updates

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.