{"id":"CVE-2025-66558","title":"Nextcloud Twofactor WebAuthn is the WebAuthn Two-Factor Provider for Nextcloud","summary":"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 rand…","severity":"low","cvss":3.1,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N","cwe":["CWE-639"],"vendor":"nextcloud","product":"two-factor_webauthn","affected":["two-factor_webauthn >= 1.0.0, < 1.4.2","two-factor_webauthn >= 2.0.0, < 2.4.1"],"patched":["two-factor_webauthn 2.4.1"],"published":"2025-12-05","updated":"2026-10-15","sourceUpdated":"2026-10-15T21:10:00.327","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-66558","references":[{"url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-fr8x-mvjg-wf9q","label":"security-advisories@github.com"},{"url":"https://github.com/nextcloud/twofactor_webauthn/commit/5d2302166d31ee2e01b2e21556bd5372156da13d","label":"security-advisories@github.com"},{"url":"https://github.com/nextcloud/twofactor_webauthn/pull/881","label":"security-advisories@github.com"},{"url":"https://hackerone.com/reports/3360354","label":"security-advisories@github.com"}],"tags":["nvd"],"epss":0.00278,"epssPercentile":0.20166,"ingestedAt":"2026-10-27T18:12:09.281Z","slug":"CVE-2025-66558","body":"## Overview\n\nNextcloud 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.\n\n## Affected\n\n- `two-factor_webauthn >= 1.0.0, < 1.4.2`\n- `two-factor_webauthn >= 2.0.0, < 2.4.1`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `two-factor_webauthn 2.4.1`","depth":"sunlit","depthScore":17,"depthScoreParts":{"impact":17.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}