CVE-2026-6339
4.3
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Exploitability: 2.8 / Impact: 1.4
Source: NVD
Description
Mattermost versions 11.5.x <= 11.5.1, 11.4.x <= 11.4.3 fail to validate the X-Requested-With header on the burn-on-read reveal endpoint which allows an authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost Advisory ID: MMSA-2026-00636
Affected (2)
Products: Mattermost: Mattermost Server
Configuration A
| Vulnerable Software | Affected Versions |
|---|---|
| From 11.4.0 to 11.4.4 |
References (1)
Timeline
No history available yet.