CVEvulnerability

CVE-2026-6339

4.3 MEDIUM Published 2026-05-18 Modified 2026-10-14 Official page ↗
Status
Analyzed
Published
2026-05-18
Last modified
2026-10-14
Assigner
[email protected]
CVSS 3.1 ([email protected])
4.3 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CVSS 3.1 ([email protected])
4.3 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weaknesses
CWE-346

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 configurations

• mattermost mattermost server (>= 11.4.0 < 11.4.4) • mattermost mattermost server (>= 11.5.0 < 11.5.2)

Related

Weakness · CWE (1)

  • CWE-346 Origin Validation Error weakness

References