CVE-2026-8683 Overly long URLs crash the Mattermost Desktop App

Mattermost Desktop App versions =6.1 5.5.13.0 fail to account for attempting to open extremely long URLs in the Mattermost Desktop App which allows a malicious server owner to crash the application via including a script to call window.open on a very large URL. Mattermost Advisory ID:...

CVE-2026-6517 Mattermost Desktop App fails to restrict the allow list of domains which NTLM credentials are passed

Mattermost Desktop App versions =6.1 5.5.13.0 fail to restrict the allow list of domains to which NTLM credentials were forwarded to in the Mattermost Desktop App which allows any user on a server without the image proxy enabled to intercept other users credentials via embedding an image that...

CVE-2026-6517 Mattermost Desktop App fails to restrict the allow list of domains which NTLM credentials are passed

Mattermost Desktop App versions =6.1 5.5.13.0 fail to restrict the allow list of domains to which NTLM credentials were forwarded to in the Mattermost Desktop App which allows any user on a server without the image proxy enabled to intercept other users credentials via embedding an image that...

CVE-2026-6517 Mattermost Desktop App fails to restrict the allow list of domains which NTLM credentials are passed

Mattermost Desktop App versions =6.1 5.5.13.0 fail to restrict the allow list of domains to which NTLM credentials were forwarded to in the Mattermost Desktop App which allows any user on a server without the image proxy enabled to intercept other users credentials via embedding an image that...

PT-2026-49243

Name of the Vulnerable Software and Affected Versions Mattermost Desktop App versions prior to 6.1 Mattermost Desktop App version 5.5.13.0 Description The application fails to properly handle attempts to open extremely long URLs. A malicious server owner can cause the application to crash by...

EUVD-2026-36625

OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted conte...

Insufficient Session Expiration

Overview @openclaw/mattermost is an OpenClaw Mattermost channel plugin Affected versions of this package are vulnerable to Insufficient Session Expiration due to a delay in the monitor refresh process. An attacker can continue to execute unauthorized commands by exploiting the acceptance of revok...

Not Failing Securely ('Failing Open')

Overview @openclaw/mattermost is an OpenClaw Mattermost channel plugin Affected versions of this package are vulnerable to Not Failing Securely 'Failing Open' in the event handler process due to missing validation of channel type metadata. An attacker can bypass intended policy decisions by sendi...

CVE-2026-53837

OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted conte...

CVE-2026-53837 OpenClaw < 2026.5.6 - Missing Channel Type Validation in Mattermost Event Handlers

OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted conte...

CVE-2026-53837 OpenClaw < 2026.5.6 - Missing Channel Type Validation in Mattermost Event Handlers

OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted conte...

CVE-2026-53837 OpenClaw < 2026.5.6 - Missing Channel Type Validation in Mattermost Event Handlers

OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted conte...

CVE-2026-53837

CVE-2026-53837 affects OpenClaw prior to 2026.5.6, where an improper access control vulnerability in Mattermost event handlers fails to validate channel type metadata. Attackers can bypass DM policy decisions by sending crafted Mattermost events that omit channel type information, enabling proces...

CVE-2026-53824 Mattermost plugin for OpenClaw < 2026.4.24 - Slash Token Revocation Lag via Monitor Refresh Delay

OpenClaw before 2026.4.24 contains a token revocation vulnerability allowing callers with revoked slash tokens to continue executing commands during monitor refresh windows. Attackers can exploit stale token acceptance to invoke slash command behavior briefly after token revocation, potentially...

CVE-2026-53824 Mattermost plugin for OpenClaw < 2026.4.24 - Slash Token Revocation Lag via Monitor Refresh Delay

OpenClaw before 2026.4.24 contains a token revocation vulnerability allowing callers with revoked slash tokens to continue executing commands during monitor refresh windows. Attackers can exploit stale token acceptance to invoke slash command behavior briefly after token revocation, potentially...

CVE-2026-53824 Mattermost plugin for OpenClaw < 2026.4.24 - Slash Token Revocation Lag via Monitor Refresh Delay

OpenClaw before 2026.4.24 contains a token revocation vulnerability allowing callers with revoked slash tokens to continue executing commands during monitor refresh windows. Attackers can exploit stale token acceptance to invoke slash command behavior briefly after token revocation, potentially...

GHSA-8QQ9-CQJ8-82W4 Mattermost doesn't sanitize FileInfo.Name received from federated peers during shared channel file sync

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 sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the targ...

GHSA-C28Q-M4GF-VG4Q Mattermost doesn't enforce PermissionInviteUser when setting AllowOpenInvite or AllowedDomains during team creation

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...

GHSA-RP4V-QC77-PHM4 Mattermost doesn't restrict role_updated websocket event broadcasts to members of the affected team or channel

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...

GHSA-M2W9-H2MM-79QR Mattermost doesn't require system-level permission when patching 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...