Auth bypass in Yubico Pam-u2f

CVE-2021-31924

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…

Vulnerability class: Broken Authentication

EPSS: 0.003 (25.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-31924?
CVE-2021-31924 is a medium-severity vulnerability in Yubico Pam-u2f, classified under Improper Authentication. CVSS score: 6.8/10. Published 2021-05-26.
How severe is CVE-2021-31924?
Medium severity. CVSS v3 base score is 6.8 out of 10.
Is CVE-2021-31924 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.