{"id":"CVE-2026-3471","state":"PUBLISHED","title":"Opening a window with {{javascript:alert()}} as URL causes crash in the Mattermost Desktop App","description":"Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent an invalid URL from loading in a pop-up window in the Mattermost Desktop App which allows a malicious server owner to repeated crash the application via calling {{window.open('javascript:alert()');}}. Mattermost Advisory ID: MMSA-2026-00618","publishedAt":"2026-05-18T08:45:44.576Z","updatedAt":"2026-05-18T14:35:23.933Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","source":"Mattermost"},"assigner":"Mattermost","products":["Mattermost Mattermost"],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"6.0.1","versionType":"semver"},{"version":"0","status":"affected","lessThanOrEqual":"5.4.13","versionType":"semver"},{"version":"6.2.0","status":"unaffected"},{"version":"6.1.1.0","status":"unaffected"},{"version":"5.13.5.0","status":"unaffected"}]}],"references":["https://mattermost.com/security-updates"],"weaknesses":["CWE-939"],"ingestedAt":"2026-10-29T20:11:50.837Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/3xxx/CVE-2026-3471.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-3471","state":"PUBLISHED","datePublished":"2026-05-18T08:45:44.576Z","dateUpdated":"2026-05-18T14:35:23.933Z","assignerShortName":"Mattermost","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateReserved":"2026-03-03T10:41:41.370Z"},"containers":{"cna":{"title":"Opening a window with {{javascript:alert()}} as URL causes crash in the Mattermost Desktop App","descriptions":[{"lang":"en","value":"Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent an invalid URL from loading in a pop-up window in the Mattermost Desktop App which allows a malicious server owner to repeated crash the application via calling {{window.open('javascript:alert()');}}. Mattermost Advisory ID: MMSA-2026-00618"}],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"6.0.1","versionType":"semver"},{"version":"0","status":"affected","lessThanOrEqual":"5.4.13","versionType":"semver"},{"version":"6.2.0","status":"unaffected"},{"version":"6.1.1.0","status":"unaffected"},{"version":"5.13.5.0","status":"unaffected"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00618","tags":["vendor-advisory"]}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","baseSeverity":"MEDIUM","baseScore":6.5},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-939","lang":"en","type":"CWE","description":"CWE-939: Improper Authorization in Handler for Custom URL Scheme"}]}],"providerMetadata":{"shortName":"Mattermost","orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateUpdated":"2026-05-18T08:45:44.576Z"},"credits":[{"lang":"en","type":"finder","value":"game0v3r"}],"solutions":[{"value":"Update Mattermost Desktop App to versions 6.2.0, 6.1.1.0, 5.13.5.0 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2026-00618","defect":["https://mattermost.atlassian.net/browse/MM-67756"],"discovery":"EXTERNAL"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-18T14:34:41.218853Z","id":"CVE-2026-3471","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":"2026-05-18T14:35:23.933Z"}}]}}}