GO-2026-5245 Mattermost: Authenticated DoS through failure to prevent rendering of external SVGs on link embeds in github.com/mattermost/mattermost-server

Mattermost: Authenticated DoS through failure to prevent rendering of external SVGs on link embeds in github.com/mattermost/mattermost-server...

GO-2026-5263 Mattermost doesn't verify channel membership when processing AI-assisted message rewrites in github.com/mattermost/mattermost-server

Mattermost doesn't verify channel membership when processing AI-assisted message rewrites in github.com/mattermost/mattermost-server. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. If this is causing...

GO-2026-5153 Mattermost MS Teams plugin doesn't limit the request body size on the /changes webhook endpoint in github.com/mattermost/mattermost-plugin-msteams

Mattermost MS Teams plugin doesn't limit the request body size on the /changes webhook endpoint in github.com/mattermost/mattermost-plugin-msteams...

GO-2026-5067 Mattermost allows attackers to manipulate administrator terminals via crafted messages containing ANSI and OSC escape sequences in github.com/mattermost/mattermost-server

Mattermost allows attackers to manipulate administrator terminals via crafted messages containing ANSI and OSC escape sequences in github.com/mattermost/mattermost-server...

GO-2026-5092 Mattermost allows system administrators to read arbitrary host files via malicious AdvancedLoggingJSON configuration in github.com/mattermost/mattermost-server

Mattermost allows system administrators to read arbitrary host files via malicious AdvancedLoggingJSON configuration in github.com/mattermost/mattermost-server...

GO-2026-5112 Mattermost doesn't set permissions on downloaded bulk export in github.com/mattermost/mattermost-server

Mattermost doesn't set permissions on downloaded bulk export in github.com/mattermost/mattermost-server. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. If this is causing false-positive reports from...

GO-2026-5173 Mattermost has an Incorrect Authorization issue in github.com/mattermost/mattermost-server

Mattermost has an Incorrect Authorization issue in github.com/mattermost/mattermost-server...

PT-2026-52566

Name of the Vulnerable Software and Affected Versions Mattermost Google Drive plugin versions prior to 1.1.0 Description An improper access control issue exists where the plugin fails to validate channel membership in the file creation endpoint. This allows authenticated users with a connected...

CVE-2026-46548

NocoDB (CVE-2026-46548 ) exhibits an SSRF protection bypass in the notification webhook plugins for Slack, Discord, Mattermost, and Teams. Root cause: in the affected code paths, the httpAgent/httpsAgent were incorrectly placed in the request body of axios.post instead of the config argument, all...

CVE-2026-8823

Mattermost versions 11.7.x = 11.7.0, 10.11.x = 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669...

CVE-2026-9162

Mattermost versions 11.7.x = 11.7.0, 11.6.x = 11.6.2, 11.5.x = 11.5.5, 10.11.x = 10.11.17 fail to invalidate cached authentication state for active WebSocket connections during global session revocation, which allows a user with an existing WebSocket connection to remain authenticated and continu...

CVE-2026-8074

Mattermost versions 11.7.x = 11.7.0, 10.11.x = 10.11.17 fail to enforce bot-specific permission checks on the user active status endpoint, which allows a User Manager with user management write access but no Integrations access to deactivate bot accounts via the PUT /api/v4/users/id/active API...

CVE-2026-6062

Mattermost versions 11.7.x = 11.7.0, 11.6.x = 11.6.2, 11.5.x = 11.5.5, 10.11.x = 10.11.17 Fail to validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to via a crafted PUT...

CVE-2026-6673

Mattermost versions 11.7.x = 11.7.0, 11.6.x = 11.6.2, 11.5.x = 11.5.5, 10.11.x = 10.11.17 fail to authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret and disrupt the Jira integration via POST to /ac/installed during the...

CVE-2026-5139

Mattermost versions 11.7.x slash command.. Mattermost Advisory ID: MMSA-2026-00644...

CVE-2026-8823 User Manager can demote bot accounts to guest without bot-management permission

Mattermost versions 11.7.x = 11.7.0, 10.11.x = 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669...

EUVD-2026-38276

Mattermost versions 11.7.x = 11.7.0, 10.11.x = 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669...

CVE-2026-8823

Mattermost versions 11.7.x = 11.7.0, 10.11.x = 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669...

CVE-2026-8823

Mattermost versions affected are 11.7.x <= 11.7.0 and 10.11.x

CVE-2026-8823 User Manager can demote bot accounts to guest without bot-management permission

Mattermost versions 11.7.x = 11.7.0, 10.11.x = 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669...