CVE-2011-4120: Debian Linux

Critical severity, CVSS 9.8. EPSS: 2% chance of exploitation in the next 30 days.

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 Debian Linux: version 8.0 only; version 9.0 only; version 10.0 only
• Yubico Pam Module: before 2.10 (fixed in 2.10)

Published 2019-11-26. Last modified 2026-06-16.