CVE-2026-20719

Mattermost versions 11.4.x = 11.4.0, 11.3.x = 11.3.1, 11.2.x = 11.2.3, 10.11.x = 10.11.11 fail to prevent rendering of external SVGs on link embeds which allows unauthenticated users to crash the Mattermost webapp and desktop app via creating an issue or PR on GitHub.. Mattermost Advisory ID:...

Mattermost: Authenticated DoS through failure to prevent rendering of external SVGs on link embeds

Mattermost versions 11.4.x = 11.4.0, 11.3.x = 11.3.1, 11.2.x = 11.2.3, 10.11.x = 10.11.11 fail to prevent rendering of external SVGs on link embeds which allows unauthenticated users to crash the Mattermost webapp and desktop app via creating an issue or PR on GitHub. Mattermost Advisory ID:...

Improper Check for Unusual or Exceptional Conditions

Overview github.com/mattermost/mattermost/server/channels/app is a private-cloud Slack alternative Affected versions of this package are vulnerable to Improper Check for Unusual or Exceptional Conditions through the rendering process of external SVGs on link embeds. An attacker can cause the web...

CVE-2026-20719 DoS via URL Previews Rendering Malicious SVGs

Mattermost versions 11.4.x = 11.4.0, 11.3.x = 11.3.1, 11.2.x = 11.2.3, 10.11.x = 10.11.11 fail to prevent rendering of external SVGs on link embeds which allows unauthenticated users to crash the Mattermost webapp and desktop app via creating an issue or PR on GitHub.. Mattermost Advisory ID:...