cvedb.io
CVE-2021-31924
MEDIUM · CVSS 6.8
EPSS exploitation probability: 0%
Published 2021-05-26T00:15:08.490 · Last modified 2026-06-17T03:52:30.123

Summary

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.

Affected products

yubico — pam-u2f

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.