medium6.3
CVE-2026-6517
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…
Impact
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
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Mattermost | Mattermost Desktop | through 5.13.0 from 6.1.0 through 6.1.5 |