Medium severity4.3NVD Advisory· Published Aug 17, 2026· Updated Aug 18, 2026
CVE-2026-16047
CVE-2026-16047
Description
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
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
2cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*range: >=10.11.0,<10.11.22
- (no CPE)range: <=11.7.6, <=10.11.21, <=11.8.3
Patches
Vulnerability mechanics
References
1- mattermost.com/security-updatesnvdVendor Advisory
News mentions
1- Mattermost: Twelve Vulnerabilities Disclosed, Including High-Severity Permission FlawsVypr Intelligence · Aug 17, 2026