CVE-2026-9816

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21, 11.8.x = 11.8.3 fail to validate BoardMember.Scheme fields server-side on insert and archive-import paths which allows a board editor or non-guest team member to grant board admin to arbitrary users via POST /api/v2/boards/boardID/members a...

CVE-2026-10527

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21, 11.8.x = 11.8.3 fails to reconcile SchemeAdmin flags with a user's current role which allows a user demoted to System Guest to retain Board Admin privileges and perform admin-only operations via the Boards REST API or UI.. Mattermost Adviso...

CVE-2026-10527 Boards plugin retains Board Admin rights for users demoted to System Guest

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21, 11.8.x = 11.8.3 fails to reconcile SchemeAdmin flags with a user's current role which allows a user demoted to System Guest to retain Board Admin privileges and perform admin-only operations via the Boards REST API or UI.. Mattermost Adviso...

EUVD-2026-60192

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21, 11.8.x = 11.8.3 fails to reconcile SchemeAdmin flags with a user's current role which allows a user demoted to System Guest to retain Board Admin privileges and perform admin-only operations via the Boards REST API or UI.. Mattermost Adviso...

CVE-2026-16044 Insufficient validation of guest board admin privileges on archive import

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive import which allows a board member to escalate a guest user to Board Admin via importing a crafted .boardarchive file. Mattermost Advisory ID:...

CVE-2026-16044

Mattermost versions 11.7.6 and 10.11.21 fail to validate guest user privileges during board archive import, allowing a board member to escalate a guest user to Board Admin via a crafted .boardarchive file. CVSS 5.4 (MEDIUM). No exploitation details or patch version are provided. Upgrade to a fixe...

CVE-2026-16044 Insufficient validation of guest board admin privileges on archive import

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive import which allows a board member to escalate a guest user to Board Admin via importing a crafted .boardarchive file. Mattermost Advisory ID:...

EUVD-2026-60211

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive import which allows a board member to escalate a guest user to Board Admin via importing a crafted .boardarchive file. Mattermost Advisory ID:...

CVE-2026-16044

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive import which allows a board member to escalate a guest user to Board Admin via importing a crafted .boardarchive file. Mattermost Advisory ID:...

PT-2026-76667

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21, 11.8.x = 11.8.3 fails to reconcile SchemeAdmin flags with a user's current role which allows a user demoted to System Guest to retain Board Admin privileges and perform admin-only operations via the Boards REST API or UI.. Mattermost Adviso...

PT-2026-76669

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive import which allows a board member to escalate a guest user to Board Admin via importing a crafted .boardarchive file. Mattermost Advisory ID:...

PT-2026-76876

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21, 11.8.x = 11.8.3 fail to validate BoardMember.Scheme fields server-side on insert and archive-import paths which allows a board editor or non-guest team member to grant board admin to arbitrary users via POST /api/v2/boards/boardID/members a...

CVE-2023-28485

A stored cross-site scripting Stored XSS vulnerability in file preview in WeKan before 6.75 allows remote authenticated users to inject arbitrary web script or HTML via names of file attachments. Any user can obtain the privilege to rename within their own board where they have BoardAdmin access,...

SQL-Injection in MyBulletinBoard allows attacker to become a board admin.

Vendor: www.mybboard.com Version: 1.00 Preview Release 2, RC4 and mayb prior. Script: usercp.php Code: if$mybb-input'away' == "yes" && $mybb-settings'allowaway' != "no" ... $returndate = $mybb-input'awayday'."-".$mybb-input'awaymonth'."-".$mybb-input'awayyear'; ... $newprofile = array "website" =...