Vulnerability Monitor

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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.

Published

2025-12-05T18:15:59.140

Last Modified

2025-12-09T16:44:58.910

Status

Analyzed

Source

[email protected]

Severity

CVSSv3.1: 3.1 (LOW)

Weaknesses

Type: Secondary
CWE-639

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	nextcloud	two-factor_webauthn	< 1.4.2	Yes
Application	nextcloud	two-factor_webauthn	< 2.4.1	Yes

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-fr8x-mvjg-wf9q Patch, Vendor Advisory ([email protected])
https://github.com/nextcloud/twofactor_webauthn/commit/5d2302166d31ee2e01b2e21556bd5372156da13d Patch ([email protected])
https://github.com/nextcloud/twofactor_webauthn/pull/881 Issue Tracking, Patch ([email protected])
https://hackerone.com/reports/3360354 Permissions Required, Vendor Advisory ([email protected])