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CVE-2026-6850

nvd nist
Published: Jul 13, 2026Modified: Jul 13, 2026

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6.5
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Exploitability: 2.8 / Impact: 3.6
Source: responsibledisclosure@mattermost.com (Secondary)

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

Affected (3)

Mattermost
1 product
Mattermost Server
Configuration A
3 vulnerable
Vulnerable SoftwareAffected Versions
Mattermost
Mattermost Server
From 10.11.0 to 10.11.20
Mattermost Server
From 11.6.0 to 11.6.5
Mattermost Server
From 11.7.0 to 11.7.3

Related CWEs

CWE-1333
Inefficient Regular Expression Complexity
The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.

References (1)

Source: responsibledisclosure@mattermost.com
Vendor Advisory

Timeline

No history available yet.