CVE-2026-14259

Name of the Vulnerable Software and Affected Versions Mattermost version 11.9.0 Mattermost version 11.8.4 Mattermost version 11.7.7 Mattermost version 10.11.22

Description An issue exists where board creation permissions are not enforced during the import of archive files. This allows an authenticated non-guest team member to bypass administrator restrictions and create Open or Private boards by importing a specially crafted .boardarchive file.

Recommendations Update Mattermost version 11.9.0 to a newer version. Update Mattermost version 11.8.4 to a newer version. Update Mattermost version 11.7.7 to a newer version. Update Mattermost version 10.11.22 to a newer version.