GO-2025-3407 Mattermost webapp crash via a crafted post in github.com/mattermost/mattermost-server

Mattermost webapp crash via a crafted post in github.com/mattermost/mattermost-server...

Mattermost webapp crash via a crafted post

Mattermost versions 10.2.x = 10.2.0, 9.11.x = 9.11.5, 10.0.x = 10.0.3, 10.1.x = 10.1.3 fail to properly handle posts with attachments containing fields that cannot be cast to a String, which allows an attacker to cause the webapp to crash via creating and sending such a post to a channel...

CVE-2025-20621

Summary (CVE-2025-20621) Mattermost webapp crashes when processing posts with attachments containing fields that cannot be cast to a String. Affected versions include Mattermost 10.2.x <= 10.2.0, 9.11.x <= 9.11.5, 10.0.x <= 10.0.3, and 10.1.x