CVE-2026-16047

Mattermost versions 11.7.x ≤ 11.7.6, 10.11.x ≤ 10.11.21, and 11.8.x ≤ 11.8.3 contain an authorization flaw in the board-to-channel linking functionality. The server fails to verify that the requesting user has read access to a target channel before associating a board with it. An authenticated us...

CVE-2026-16047: Missing Authorization

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...