{"id":"CVE-2026-45156","summary":"Nextcloud: Authentication Bypass in ID4me handling via Missing JWT Signature Verification in User OIDC","details":"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.","aliases":["GHSA-qqgv-fqwp-mjpp"],"modified":"2026-07-15T01:49:01.208973905Z","published":"2026-06-01T16:38:46.470Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-287"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45156.json"},"references":[{"type":"WEB","url":"https://hackerone.com/reports/3489490"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45156.json"},{"type":"ADVISORY","url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qqgv-fqwp-mjpp"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45156"},{"type":"FIX","url":"https://github.com/nextcloud/user_oidc/pull/1285"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nextcloud/user_oidc","events":[{"introduced":"e4f152c1bd3e3bb51e8434b4dfb5850712d77271"},{"fixed":"a291ea5500abf549798399e8cea13396af8d7303"},{"introduced":"48af954cb7456d4d6f4aeece9bb2908e8184fa3a"},{"fixed":"b2fef06293b26fa1085faf75e59f0e370ea86494"},{"introduced":"1053b625796f9bc80ae9947fd22b2fb953dbf70a"},{"fixed":"3427640c101bfa3b0466ee3d7f1d8b5f54113bf3"}],"database_specific":{"extracted_events":[{"introduced":"0.3.0"},{"fixed":"3.1.0"},{"introduced":"5.0.0"},{"fixed":"5.1.0"},{"introduced":"6.0.0"},{"fixed":"6.4.0"}],"source":"AFFECTED_FIELD"}}],"versions":["v3.0.0","v6.3.1","v6.3.0","v6.2.1","v6.2.0","v6.1.2","v6.1.1","v6.1.0","v6.0.1","v6.0.0","v5.0.3","v5.0.2","v5.0.1","v5.0.0","v0.3.2","v1.2.0","v1.3.3","v1.3.2","v1.3.1","v1.3.0","v1.2.1","v1.1.0","v1.0.0","v0.3.1","v0.3.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45156.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N"}]}