{"api_version":"1","generated_at":"2026-06-03T09:09:13+00:00","cve":"CVE-2026-3471","urls":{"html":"https://cve.report/CVE-2026-3471","api":"https://cve.report/api/cve/CVE-2026-3471.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-3471","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-3471"},"summary":{"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","state":"PUBLISHED","assigner":"Mattermost","published_at":"2026-05-18 09:16:22","updated_at":"2026-05-18 17:32:38"},"problem_types":["CWE-939","CWE-939 CWE-939: Improper Authorization in Handler for Custom URL Scheme"],"metrics":[{"version":"3.1","source":"responsibledisclosure@mattermost.com","type":"Secondary","score":"6.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","baseScore":6.5,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"CVSS","score":"6.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","data":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://mattermost.com/security-updates","name":"https://mattermost.com/security-updates","refsource":"responsibledisclosure@mattermost.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-3471","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-3471","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Mattermost","product":"Mattermost","version":"affected 6.0.1 semver","platforms":[]},{"source":"CNA","vendor":"Mattermost","product":"Mattermost","version":"affected 5.4.13 semver","platforms":[]},{"source":"CNA","vendor":"Mattermost","product":"Mattermost","version":"unaffected 6.2.0","platforms":[]},{"source":"CNA","vendor":"Mattermost","product":"Mattermost","version":"unaffected 6.1.1.0","platforms":[]},{"source":"CNA","vendor":"Mattermost","product":"Mattermost","version":"unaffected 5.13.5.0","platforms":[]}],"timeline":[],"solutions":[{"source":"CNA","title":"","value":"Update Mattermost Desktop App to versions 6.2.0, 6.1.1.0, 5.13.5.0 or higher.","time":"","lang":"en"}],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"game0v3r","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"3471","cve":"CVE-2026-3471","epss":"0.000380000","percentile":"0.114050000","score_date":"2026-05-26","updated_at":"2026-05-27 00:01:53"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-3471","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-05-18T14:34:41.218853Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-05-18T14:35:23.933Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"defaultStatus":"unaffected","product":"Mattermost","vendor":"Mattermost","versions":[{"lessThanOrEqual":"6.0.1","status":"affected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.4.13","status":"affected","version":"0","versionType":"semver"},{"status":"unaffected","version":"6.2.0"},{"status":"unaffected","version":"6.1.1.0"},{"status":"unaffected","version":"5.13.5.0"}]}],"credits":[{"lang":"en","type":"finder","value":"game0v3r"}],"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"}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","version":"3.1"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-939","description":"CWE-939: Improper Authorization in Handler for Custom URL Scheme","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-05-18T08:45:44.576Z","orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","shortName":"Mattermost"},"references":[{"name":"MMSA-2026-00618","tags":["vendor-advisory"],"url":"https://mattermost.com/security-updates"}],"solutions":[{"lang":"en","value":"Update Mattermost Desktop App to versions 6.2.0, 6.1.1.0, 5.13.5.0 or higher."}],"source":{"advisory":"MMSA-2026-00618","defect":["https://mattermost.atlassian.net/browse/MM-67756"],"discovery":"EXTERNAL"},"title":"Opening a window with {{javascript:alert()}} as URL causes crash in the Mattermost Desktop App","x_generator":{"engine":"cvelib 1.8.0"}}},"cveMetadata":{"assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","assignerShortName":"Mattermost","cveId":"CVE-2026-3471","datePublished":"2026-05-18T08:45:44.576Z","dateReserved":"2026-03-03T10:41:41.370Z","dateUpdated":"2026-05-18T14:35:23.933Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-18 09:16:22","lastModifiedDate":"2026-05-18 17:32:38","problem_types":["CWE-939","CWE-939 CWE-939: Improper Authorization in Handler for Custom URL Scheme"],"metrics":{"cvssMetricV31":[{"source":"responsibledisclosure@mattermost.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","baseScore":6.5,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":2.8,"impactScore":3.6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"3471","Ordinal":"1","Title":"Opening a window with {{javascript:alert()}} as URL causes crash","CVE":"CVE-2026-3471","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"3471","Ordinal":"1","NoteData":"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","Type":"Description","Title":"Opening a window with {{javascript:alert()}} as URL causes crash"}]}}}