CVE-2011-4120
CVE-2011-4120 is a critical-severity vulnerability in Yubico Pam Module with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- CVSS v2: 7.5
- EPSS exploit prediction: 2% (79th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-20
- Affected product: Yubico Pam Module
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2011-4120?
- 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.
- How severe is CVE-2011-4120?
- CVE-2011-4120 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2011-4120 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2011-4120?
- CVE-2011-4120 primarily affects Yubico Pam Module. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2011-4120?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- When was CVE-2011-4120 published?
- CVE-2011-4120 was published on 2019-11-26 and last updated on 2026-06-16.
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
Affected products (4)
- cpe:2.3:a:yubico:pam_module:*:*:*:*:*:*:*:*
- cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
- cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
- cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
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