CVE-2025-66558

Dec. 9, 2025, 4:44 p.m.

3.1
Low

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.

Product(s) Impacted

Vendor Product Versions
Nextcloud
  • Two-factor Webauthn
  • *

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-639
Authorization Bypass Through User-Controlled Key
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
a nextcloud two-factor_webauthn / / / / / / / /
a nextcloud two-factor_webauthn / / / / / / / /

CVSS Score

3.1 / 10

CVSS Data - 3.1

  • Attack Vector: NETWORK
  • Attack Complexity: HIGH
  • Privileges Required: LOW
  • Scope: UNCHANGED
  • Confidentiality Impact: NONE
  • Integrity Impact: LOW
  • Availability Impact: NONE
  • CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N

    View Vector String

Timeline

Published: Dec. 5, 2025, 6:15 p.m.
Last Modified: Dec. 9, 2025, 4:44 p.m.

Status : Analyzed

CVE has had analysis completed and all data associations made.

More info

Source

security-advisories@github.com

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.