{"id":"CVE-2026-6517","state":"PUBLISHED","title":"Mattermost Desktop App fails to restrict the allow list of domains which NTLM credentials are passed","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","publishedAt":"2026-06-15T13:55:25.742Z","updatedAt":"2026-06-15T16:00:00.919Z","severity":{"score":6.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","source":"Mattermost"},"assigner":"Mattermost","products":["Mattermost Mattermost"],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"5.5.13","versionType":"semver"},{"version":"6.2.0","status":"unaffected"},{"version":"5.13.6.0","status":"unaffected"}]}],"references":["https://mattermost.com/security-updates"],"weaknesses":["CWE-522"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/6xxx/CVE-2026-6517.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-6517","state":"PUBLISHED","datePublished":"2026-06-15T13:55:25.742Z","dateUpdated":"2026-06-15T16:00:00.919Z","assignerShortName":"Mattermost","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateReserved":"2026-04-17T14:25:10.246Z"},"containers":{"cna":{"title":"Mattermost Desktop App fails to restrict the allow list of domains which NTLM credentials are passed","descriptions":[{"lang":"en","value":"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":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"5.5.13","versionType":"semver"},{"version":"6.2.0","status":"unaffected"},{"version":"5.13.6.0","status":"unaffected"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00651","tags":["vendor-advisory"]}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","baseSeverity":"MEDIUM","baseScore":6.3},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-522","lang":"en","type":"CWE","description":"CWE-522: Insufficiently Protected Credentials"}]}],"providerMetadata":{"shortName":"Mattermost","orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateUpdated":"2026-06-15T13:55:25.742Z"},"credits":[{"lang":"en","type":"finder","value":"falke"}],"solutions":[{"value":"Update Mattermost Desktop App to versions 6.2.0, 5.13.6.0 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2026-00651","defect":["https://mattermost.atlassian.net/browse/MM-68362"],"discovery":"EXTERNAL"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-15T15:59:27.291763Z","id":"CVE-2026-6517","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-15T16:00:00.919Z"}}]}}}