{"id":"CVE-2026-45156","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-45156","generatedAt":"2026-10-28T04:45:31.831Z","title":"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.","description":"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.","published":"2026-06-01T17:17:09.000Z","lastModified":"2026-07-22T07:10:00.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":8.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N"},"cwe":["CWE-287"],"affected":[],"epss":{"score":0.00412,"percentile":0.35246,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.41%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qqgv-fqwp-mjpp","source":"security-advisories@github.com"},{"url":"https://github.com/nextcloud/user_oidc/pull/1285","source":"security-advisories@github.com"},{"url":"https://hackerone.com/reports/3489490","source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-45156","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}