Nextcloud Twofactor WebAuthn app was updated based on public key

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.

Scores

EPSS (exploitation in 30 days)

0.30% · top 77% of all CVEs (7 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 3.1.

Weakness

• CWE-639: Authorization Bypass Through User-Controlled Key (opens in a new tab)All about CWE-639 and its CVEs

Affected products

• nextcloud · security-advisories

  • affected < 1.4.2
  • affected >= 2.0.0-beta.1, < 2.4.1

References (4)

• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-fr8x-mvjg-wf9q (opens in a new tab)x_refsource_CONFIRM
• https://github.com/nextcloud/twofactor_webauthn/pull/881 (opens in a new tab)x_refsource_MISC
• https://github.com/nextcloud/twofactor_webauthn/commit/5d2302166d31ee2e01b2e21556bd5372156da13d (opens in a new tab)x_refsource_MISC
• https://hackerone.com/reports/3360354 (opens in a new tab)x_refsource_MISC

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2025-66558](https://trackcve.app/badge/CVE-2025-66558.svg)](https://trackcve.app/cve/CVE-2025-66558)

Record last updated 5 Dec 2025, 18:35 UTC.