PT-2026-57661 · Mattermost · Mattermost

Published

2026-07-13

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Updated

2026-07-13

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CVE-2026-6850

CVSS v3.1

6.5

Medium

VectorAV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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

Fix

DoS

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Weakness Enumeration

Related Identifiers

CVE-2026-6850

Affected Products

Mattermost