CVE-2021-31924
MEDIUMDescription
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.
How to fix
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 25% of all known CVEs.
References
Related Vulnerabilities
Other CWE-287 (Improper Authentication) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-35082 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2023-35078 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2017-7921 | Critical | 9.8 | 100% | KEV | - |
| CVE-2024-7593 | Critical | 9.8 | 100% | KEV | - |
| CVE-2023-46805 | High | 8.2 | 100% | KEV + Ransom | - |
| CVE-2022-40684 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
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Markdown
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.