CVE-2026-19621

Mattermost versions 11.10.x = 11.10.0, 11.7.x = 11.7.9, 11.9.x = 11.9.1, 11.8.x = 11.8.5 fail to strip action integration secrets from post payloads before broadcasting post-deletion web socket events and returning thread API responses, which allows an authenticated channel member to obtain...

CVE-2026-19621 Mattermost leaks interactive-message integration secrets to non-admin users via post-deletion events and thread reads

Mattermost versions 11.10.x = 11.10.0, 11.7.x = 11.7.9, 11.9.x = 11.9.1, 11.8.x = 11.8.5 fail to strip action integration secrets from post payloads before broadcasting post-deletion web socket events and returning thread API responses, which allows an authenticated channel member to obtain...

CVE-2026-19621

Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, and 11.8.x

CVE-2026-19621 Mattermost leaks interactive-message integration secrets to non-admin users via post-deletion events and thread reads

Mattermost versions 11.10.x = 11.10.0, 11.7.x = 11.7.9, 11.9.x = 11.9.1, 11.8.x = 11.8.5 fail to strip action integration secrets from post payloads before broadcasting post-deletion web socket events and returning thread API responses, which allows an authenticated channel member to obtain...

CVE-2026-19621

Mattermost versions 11.10.x = 11.10.0, 11.7.x = 11.7.9, 11.9.x = 11.9.1, 11.8.x = 11.8.5 fail to strip action integration secrets from post payloads before broadcasting post-deletion web socket events and returning thread API responses, which allows an authenticated channel member to obtain...

CVE-2026-19621: Exposure of Sensitive Information to an Unauthorized Actor

Mattermost versions 11.10.x = 11.10.0, 11.7.x = 11.7.9, 11.9.x = 11.9.1, 11.8.x = 11.8.5 fail to strip action integration secrets from post payloads before broadcasting post-deletion web socket events and returning thread API responses, which allows an authenticated channel member to obtain...

Information Disclosure

github.com/mattermost/mattermost-server is vulnerable to Information Disclosure. The vulnerability exists due to not sanitizing some of the userupdated and postdeleted event broadcasts to all users which allows an attacker to gain access to sensitive information...

CVE-2023-1775

When running in a High Availability configuration, Mattermost fails to sanitize some of the userupdated and postdeleted events broadcast to all users, leading to disclosure of sensitive information to some of the users with currently connected Websocket clients...

CVE-2023-1775: Exposure of Sensitive Information to an Unauthorized Actor

When running in a High Availability configuration, Mattermost fails to sanitize some of the userupdated and postdeleted events broadcast to all users, leading to disclosure of sensitive information to some of the users with currently connected Websocket clients...