CVE-2025-66558

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 v3 3.1 LOW

3.1^/10

CVSS v3 : LOW

Vector :

Exploitability : 1.6 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-fr8x-mvjg-wf9q	Patch Vendor Advisory
https://github.com/nextcloud/twofactor_webauthn/commit/5d2302166d31ee2e01b2e21556bd5372156da13d	Patch
https://github.com/nextcloud/twofactor_webauthn/pull/881	Issue Tracking Patch
https://hackerone.com/reports/3360354	Permissions Required Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:nextcloud:two-factor_webauthn::::::::
	cpe:2.3:a:nextcloud:two-factor_webauthn::::::::

History

15 Oct 2026, 21:10

Type	Values Removed	Values Added
Summary		(es) Nextcloud Twofactor WebAuthn es el WebAuthn Two?Factor Provider para Nextcloud. Versiones anteriores a 1.4.2 y 2.4.1, una falta de verificación de propiedad permitió que un atacante tomara un dispositivo 2FA WebAuthn al adivinar correctamente una cadena aleatoria de 80?128 caracteres de letras, números y símbolos. La víctima sería entonces solicitada a registrar un nuevo dispositivo en el próximo inicio de sesión. El atacante no puede autenticarse como la víctima. Esta vulnerabilidad está corregida en 1.4.2 y 2.4.1.

Information

Published : 2025-12-05 18:15

Updated : 2026-10-15 21:10

NVD link : CVE-2025-66558

Mitre link : CVE-2025-66558

CVE.ORG link : CVE-2025-66558

JSON object : View

Products Affected

nextcloud

two-factor_webauthn

CWE

CWE-639

Authorization Bypass Through User-Controlled Key

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