{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-45156","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-05-08T20:44:38.964Z","datePublished":"2026-06-01T16:38:46.470Z","dateUpdated":"2026-06-03T03:55:47.564Z"},"containers":{"cna":{"title":"Nextcloud: Authentication Bypass in ID4me handling via Missing JWT Signature Verification in User OIDC","problemTypes":[{"descriptions":[{"cweId":"CWE-287","lang":"en","description":"CWE-287: Improper Authentication","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":8.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qqgv-fqwp-mjpp","tags":["x_refsource_CONFIRM"],"url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qqgv-fqwp-mjpp"},{"name":"https://github.com/nextcloud/user_oidc/pull/1285","tags":["x_refsource_MISC"],"url":"https://github.com/nextcloud/user_oidc/pull/1285"},{"name":"https://hackerone.com/reports/3489490","tags":["x_refsource_MISC"],"url":"https://hackerone.com/reports/3489490"}],"affected":[{"vendor":"nextcloud","product":"security-advisories","versions":[{"version":">= 0.3.0, < 3.1.0","status":"affected"},{"version":">= 5.0.0, < 5.1.0","status":"affected"},{"version":">= 6.0.0, < 6.4.0","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-06-01T16:38:46.470Z"},"descriptions":[{"lang":"en","value":"Nextcloud is an open source content collaboration platform. From versions 0.3.0 to before 3.1.0, 5.0.0 to before 5.1.0, and 6.0.0 to before 6.4.0, a missing signature verification in User OIDC allowed a malicious ID4me authority to identify as any user. This issue has been patched in versions 3.1.0, 4.1.0, 5.1.0, 6.4.0 and 8.3.0."}],"source":{"advisory":"GHSA-qqgv-fqwp-mjpp","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-02T00:00:00+00:00","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3","id":"CVE-2026-45156"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-06-03T03:55:47.564Z"}}]}}