CVE-2025-66558

3.1 LOW
Published: December 05, 2025 Modified: December 09, 2025

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.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

Login to generate AI explanation

CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-fr8x-mvjg-wf9q
Source: security-advisories@github.com
Patch Vendor Advisory
https://github.com/nextcloud/twofactor_webauthn/pull/881
Source: security-advisories@github.com
Issue Tracking Patch
https://hackerone.com/reports/3360354
Source: security-advisories@github.com
Permissions Required Vendor Advisory

4 reference(s) from NVD

Quick Stats

CVSS v3 Score
3.1 / 10.0
EPSS (Exploit Probability)
0.0%
2th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

nextcloud