CyberRota Analysis
This is a medium severity vulnerability with a CVSS score of 4.3. See the original NVD description below for full technical details.
CVE
CVE-2026-6339
Severity
MEDIUM
CVSS
4.3
EPSS
0.11%
Original 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
Related CVEs
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