What’s Vulnerable › Vulnerabilities

CVE-2011-4120

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2019-11-26 · updated 2026-06-16
• Weakness: CWE-20

Description

Yubico PAM Module before 2.10 performed user authentication when 'use_first_pass' PAM configuration option was not used and the module was configured as 'sufficient' in the PAM configuration. A remote attacker could use this flaw to circumvent common authentication process and obtain access to the account in question by providing a NULL value (pressing Ctrl-D keyboard sequence) as the password string.

Affected products

• Debian Linux: 8.0, 9.0, 10.0
• Yubico Pam Module: before 2.10 — fixed in 2.10

How to fix

Upgrade to a fixed version: Yubico Pam Module 2.10. Check the vendor advisory for mitigations.

References

• https://access.redhat.com/security/cve/cve-2011-4120
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2011-4120
• https://security-tracker.debian.org/tracker/CVE-2011-4120
• https://www.openwall.com/lists/oss-security/2011/11/07/6
• https://access.redhat.com/security/cve/cve-2011-4120
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2011-4120
• https://security-tracker.debian.org/tracker/CVE-2011-4120
• https://www.openwall.com/lists/oss-security/2011/11/07/6

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