{"cve":"CVE-2025-66558","nvd":{"published":"2025-12-05T18:15:59.140","modified":"2026-10-15T21:10:00.327","status":"Analyzed","description":"Nextcloud Twofactor WebAuthn is the WebAuthn Two-Factor Provider for Nextcloud. Prior to 1.4.2 and 2.4.1, a missing ownership check allowed an attack to take-away a 2FA webauthn device when correctly guessing a 80-128 character long random string of letters, numbers and symbols. The victim would then be prompted to register a new device on the next login. The attacker can not authenticate as the victim. This vulnerability is fixed in 1.4.2 and 2.4.1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","score":4.3},"cwes":["CWE-639"],"references":["https://github.com/nextcloud/security-advisories/security/advisories/GHSA-fr8x-mvjg-wf9q","https://github.com/nextcloud/twofactor_webauthn/commit/5d2302166d31ee2e01b2e21556bd5372156da13d","https://github.com/nextcloud/twofactor_webauthn/pull/881","https://hackerone.com/reports/3360354"],"products":["nextcloud:two-factor_webauthn"],"source":"nvd","synced_at":"2026-10-19T22:16:40.427100871+00:00"},"epss":{"cve":"CVE-2025-66558","score":0.00278,"percentile":0.20087,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}