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.
Affected products
nextcloud: two-factor webauthn
References4
- github.com/nextcloud/security-advisories/security/advisories/GH… PatchVendor Advisory
- hackerone.com/reports/3360354 Permissions RequiredVendor Advisory
- github.com/nextcloud/twofactor_webauthn/commit/5d2302166d31ee2e… Patch
- github.com/nextcloud/twofactor_webauthn/pull/881 Issue TrackingPatch
Metrics
- CVSS 3.1
-
4.3
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - EPSS — exploit probability
- 0% percentile: 23 · as of 11 November 2026
- CWE
- CWE-639
Could this be exploited in your environment?
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