A vulnerability has been found in Mattermost up to 10.11.14/11.4.4/11.5.3/11.6.0 and classified as problematic . Affected by this issue is some unknown functionality of the component Boards API . This manipulation causes authorization bypass. The identification of this vulnerability is CVE-2026-3473 . It is possible to initiate the attack remotely. There is no exploit available. The affected component should be upgraded.