Improper Check for Unusual or Exceptional Conditions

Overview Affected versions of this package are vulnerable to Improper Check for Unusual or Exceptional Conditions in the outgoing webhook process. An attacker can cause the server to terminate unexpectedly by sending a crafted webhook callback response containing a null attachment entry...

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 in the outgoing webhook process. An attacker can cause the server to terminate unexpectedly b...

CVE-2026-4915

Mattermost is affected in CVE-2026-4915 across multiple release streams (11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x

PT-2026-43013

Mattermost versions 11.6.x = 11.6.0, 11.5.x = 11.5.3, 11.4.x = 11.4.4, 10.11.x = 10.11.14 fail to filter nil elements from outgoing webhook attachment payloads before processing, which allows an authenticated user to cause a denial of service server process termination via a crafted webhook...