{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-75588","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","state":"PUBLISHED","assignerShortName":"Mattermost","dateReserved":"2026-08-17T22:19:32.227Z","datePublished":"2026-09-17T15:09:40.829Z","dateUpdated":"2026-09-17T19:22:50.101Z"},"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Mattermost","vendor":"Mattermost","versions":[{"lessThanOrEqual":"6.2.2","status":"affected","version":"0","versionType":"semver"},{"version":"6.3.0","status":"unaffected"},{"version":"6.2.3.0","status":"unaffected"}]}],"credits":[{"lang":"en","type":"finder","value":"Juho Forsén"}],"descriptions":[{"lang":"en","value":"Mattermost Desktop App versions <=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717"}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","baseSeverity":"LOW","baseScore":2.6},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"lang":"en","type":"CWE","description":"CWE-1287: Improper Validation of Specified Type of Input","cweId":"CWE-1287"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00717","tags":["vendor-advisory"]}],"solutions":[{"value":"Update Mattermost Desktop App to versions 6.3.0, 6.2.3.0 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2026-00717","defect":["https://mattermost.atlassian.net/browse/MM-69786"],"discovery":"{\"self\"=>\"https://mattermost.atlassian.net/rest/api/2/customFieldOption/10557\", \"value\"=>\"Internal\", \"id\"=>\"10557\"}"},"title":"Mattermost Desktop App plugin popout scheme validation bypass","providerMetadata":{"orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","shortName":"Mattermost","dateUpdated":"2026-09-17T15:09:40.829Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-17T19:21:58.878556Z","id":"CVE-2026-75588","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-17T19:22:50.101Z"}}]}}