{"id":"CVE-2026-6517","aliases":["EUVD-2026-36725","GHSA-2wmq-3m94-g4jr"],"status":"published","title":"Mattermost Desktop App fails to restrict the allow list of domains which NTLM credentials are passed","description":"Mattermost Desktop App versions \u003c=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","severity":{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00187,"percentile":0.08335,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-522"],"published":"2026-06-15T13:55:25Z","modified":"2026-10-28T02:30:52Z","products":[{"vendor":"mattermost","product":"mattermost"},{"vendor":"mattermost","product":"mattermost_desktop"}],"references":[{"url":"https://mattermost.com/security-updates","tags":["vendor-advisory","Vendor Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-6517","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-2wmq-3m94-g4jr"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6517.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-6517","title":"Mattermost Desktop App fails to restrict the allow list of domains which NTLM credentials are passed","description":"Mattermost Desktop App versions \u003c=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","status":"published","published":"2026-06-15T13:55:25.742Z","modified":"2026-06-15T16:00:00.919Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-522"],"updated_at":"2026-11-02T13:50:04.986624Z"}],"euvd":[{"id":"EUVD-2026-36725","description":"Mattermost Desktop App versions \u003c=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","status":"published","published":"2026-06-15T13:55:25Z","modified":"2026-06-15T16:00:00Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T18:20:41.888684Z"}],"ghsa":[{"id":"GHSA-2wmq-3m94-g4jr","title":"Mattermost Desktop App versions \u003c=6.1 5.5.13.0 fail to restrict the allow list of domains to...","description":"Mattermost Desktop App versions \u003c=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","status":"published","published":"2026-06-15T15:31:33Z","modified":"2026-06-15T15:31:39Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-522"],"updated_at":"2026-11-02T15:08:46.336077Z"}],"nvd":[{"id":"CVE-2026-6517","description":"Mattermost Desktop App versions \u003c=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","status":"published","published":"2026-06-15T14:16:37.91Z","modified":"2026-06-17T11:00:55.04Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"high","assessor":"primary"}],"cwes":["CWE-522"],"updated_at":"2026-11-02T14:12:23.846948Z"}],"osv":[{"id":"CVE-2026-6517","title":"Mattermost Desktop App fails to restrict the allow list of domains which NTLM credentials are passed","description":"Mattermost Desktop App versions \u003c=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","status":"published","published":"2026-06-15T13:55:25.742Z","modified":"2026-10-28T02:30:52.752687046Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-522"],"updated_at":"2026-11-02T15:45:14.096824Z"}]}}