Yubico pam-u2f before 1.1.1 has a logic issue that, depending on the pam-u2f configuration and the application used, could lead to a local PIN bypass. This issue does not allow user presence (touch) or cryptographic signature verification to be bypassed, so an attacker would still need to physically possess and interact with the YubiKey or another enrolled authenticator. If pam-u2f is configured to require PIN authentication, and the application using pam-u2f allows the user to submit NULL as the PIN, pam-u2f will attempt to perform a FIDO2 authentication without PIN. If this authentication is successful, the PIN requirement is bypassed.
CVSS Details
- CVSS 3.1 Base Score: 6.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade pam-u2f | Aug 22, 2024 | May 25, 2021 |
| Arch Linux | — | Upgrade to the latest version of Arch Linux | Jul 11, 2025 | May 25, 2021 |
| Debian | — | Upgrade pam-u2f | Jul 30, 2024 | May 26, 2021 |
| Gentoo Linux | — | Upgrade sys-auth/pam_u2f. | Aug 11, 2022 | May 26, 2021 |
| Suse | — | Upgrade pam_u2f | Oct 26, 2022 | May 26, 2021 |
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