VULNERABILITY INTELLIGENCE

CVE-2026-6850

CVSS score6.5 MEDIUM
EPSS probability0.42%
CISA KEVNot currently listed
Published2026-07-13
Last modified2026-07-13
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Description

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 that triggers catastrophic backtracking in the client-side markdown parser.. Mattermost Advisory ID: MMSA-2026-00658

Weakness classification

  • responsibledisclosure@mattermost.com: CWE-1333

Primary references