VULNERABILITY INTELLIGENCE

CVE-2026-6517

CVSS score6.3 MEDIUM
EPSS probability0.19%
CISA KEVNot currently listed
Published2026-06-15
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Description

Mattermost Desktop App versions <=6.1 5.5.13.0 fail to restrict the allow list of domains to which NTLM credentials were forwarded to in the Mattermost Desktop App which allows any user on a server without the image proxy enabled to intercept other users credentials via embedding an image that routes to an external web server. Mattermost Advisory ID: MMSA-2026-00651

Weakness classification

  • responsibledisclosure@mattermost.com: CWE-522

Primary references