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.
{
"cwe_ids": [
"CWE-639"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66558.json"
}{
"cpe": "cpe:2.3:a:nextcloud:two-factor_webauthn:*:*:*:*:*:*:*:*",
"source": [
"CPE_RANGE",
"REFERENCES"
],
"extracted_events": [
{
"introduced": "1.0.0"
},
{
"fixed": "1.4.2"
},
{
"introduced": "2.0.0"
},
{
"fixed": "2.4.1"
}
]
}