CVE-2026-7387 Mattermost group syncable endpoints allow privilege escalation via scheme_admin

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 Mattermost fails to require role-management authorization when setting the schemeadmin flag on group syncable link and patch endpoints, which allows a user with group-link permissions to escalate themselv...

CVE-2026-6046 Plugin bot username conflict allows user account to be used as bot identity in Mattermost Server

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 fail to validate that a username returned during bot registration belongs to a bot account, which allows an unprivileged attacker to intercept private messages sent by plugins via direct message channels ...

CVE-2026-6046

Mattermost CVE-2026-6046 affects multiple releases: 11.6.x up to 11.6.1, 11.5.x up to 11.5.4, and 10.11.x up to 10.11.16. The vulnerability arises from failing to validate that a username returned during bot registration belongs to a bot account, enabling an unprivileged attacker to intercept pri...

CVE-2026-6046 Plugin bot username conflict allows user account to be used as bot identity in Mattermost Server

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 fail to validate that a username returned during bot registration belongs to a bot account, which allows an unprivileged attacker to intercept private messages sent by plugins via direct message channels ...

CVE-2026-6046 Plugin bot username conflict allows user account to be used as bot identity in Mattermost Server

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 fail to validate that a username returned during bot registration belongs to a bot account, which allows an unprivileged attacker to intercept private messages sent by plugins via direct message channels ...

EUVD-2026-36502

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 fail to validate that a username returned during bot registration belongs to a bot account, which allows an unprivileged attacker to intercept private messages sent by plugins via direct message channels ...

EUVD-2026-36501

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 Fail to enforce PermissionInviteUser when setting AllowOpenInvite or AllowedDomains during team creation the check was only applied on update/patch, which allows an authenticated user holding...

CVE-2026-7184

Mattermost CVE-2026-7184 affects Mattermost versions 11.6.x up to 11.6.1, 11.5.x up to 11.5.4, and 10.11.x up to 10.11.15. The issue is a failure to sanitize the Remote Cluster API response on PATCH operations, allowing authenticated users with the {{manage_secure_connections}} permission to obta...

EUVD-2026-36500

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15 fail to sanitize the Remote Cluster API response on PATCH operations, which allows authenticated users with the managesecureconnections permission to obtain remote cluster authentication tokens via a PATCH request to the...

CVE-2026-7184 Mattermost Remote Cluster PATCH API Leaks Authentication Tokens

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15 fail to sanitize the Remote Cluster API response on PATCH operations, which allows authenticated users with the managesecureconnections permission to obtain remote cluster authentication tokens via a PATCH request to the...

CVE-2026-7184 Mattermost Remote Cluster PATCH API Leaks Authentication Tokens

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15 fail to sanitize the Remote Cluster API response on PATCH operations, which allows authenticated users with the managesecureconnections permission to obtain remote cluster authentication tokens via a PATCH request to the...

CVE-2026-7184 Mattermost Remote Cluster PATCH API Leaks Authentication Tokens

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15 fail to sanitize the Remote Cluster API response on PATCH operations, which allows authenticated users with the managesecureconnections permission to obtain remote cluster authentication tokens via a PATCH request to the...

CVE-2026-6739 Mattermost: Delegated admins could patch protected default system roles

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 fail to require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-i...

EUVD-2026-36499

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 fail to require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-i...

CVE-2026-6739

Mattermost vulnerability CVE-2026-6739 affects multiple releases: 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, and 10.11.x

CVE-2026-6739 Mattermost: Delegated admins could patch protected default system roles

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 fail to require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-i...

CVE-2026-6739 Mattermost: Delegated admins could patch protected default system roles

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 fail to require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-i...

CVE-2026-3433

Mattermost is affected in versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x

EUVD-2026-36498

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 fail to restrict roleupdated websocket event broadcasts to members of the affected team or channel which allows an authenticated attacker with guest-level access to observe permission scheme change...

CVE-2026-3433 Mattermost fails to scope role_updated websocket events to authorized team and channel members

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 fail to restrict roleupdated websocket event broadcasts to members of the affected team or channel which allows an authenticated attacker with guest-level access to observe permission scheme change...