EUVD-2026-43313

Mattermost versions 11.7.x = 11.7.2, 11.6.x = 11.6.4, 10.11.x = 10.11.19 fail to validate the length and content of message attachment field values, which allows an authenticated attacker to cause a denial of service for all users in a channel via a post containing a specially crafted payload tha...

CVE-2026-6850

Mattermost is affected (versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x

CVE-2026-6850 Crafted message attachment causes client-side denial of service via markdown parser regex backtracking in Mattermost

Mattermost versions 11.7.x = 11.7.2, 11.6.x = 11.6.4, 10.11.x = 10.11.19 fail to validate the length and content of message attachment field values, which allows an authenticated attacker to cause a denial of service for all users in a channel via a post containing a specially crafted payload tha...