CVE-2026-6517

medium

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

References

https://mattermost.com/security-updates

Details

Source: Mitre, NVD

Published: 2026-06-15

Updated: 2026-06-15

Risk Information

CVSS v2

Base Score: 4.9

Vector: CVSS2#AV:N/AC:H/Au:S/C:C/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 6.3

Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Severity: Medium