HOMEVULNERABILITIESCVE-2011-4120
CRITICAL

CVE-2011-4120

CWE-20Published: November 26, 2019· Updated: Jun 16, 2026

9.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2011-4120 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
Linux1 product(s)
linux kernel
yubico1 product(s)
pam module
Source: NVD CPE · 5 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

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

All References (8)

→
https://access.redhat.com/security/cve/cve-2011-4120Broken Link · Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2011-4120Issue Tracking · Patch · Third Party Advisory
→
https://security-tracker.debian.org/tracker/CVE-2011-4120Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2011/11/07/6Mailing List · Third Party Advisory
→
https://access.redhat.com/security/cve/cve-2011-4120Broken Link · Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2011-4120Issue Tracking · Patch · Third Party Advisory
→
https://security-tracker.debian.org/tracker/CVE-2011-4120Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2011/11/07/6Mailing List · Third Party Advisory

Quick Facts

CVE IDCVE-2011-4120
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-20
CISA KEVNo
Affected3 vendor(s)
PublishedNov 26, 2019

Related CVEs (CWE-20)

CVE-2007-6176
10.0
CVE-2008-6826
10.0
CVE-2021-21321
10.0
CVE-2007-6494
10.0
CVE-2008-0251
10.0
CVE-2009-0545
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2011-4120 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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