CVE-2011-4966: modules/rlm_unix/rlm_unix.c in FreeRADIUS before 2.2.0, when unix mode is enabled for user authentication, doe

Q: How do I fix CVE-2011-4966?

freeradius: upgrade to newer than 2.2.0. Exact commands for each OS are on this page.

Q: Is CVE-2011-4966 being exploited?

CVE-2011-4966 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2011-4966 affect?

CVE-2011-4966 affects freeradius. Severity is medium (CVSS 6.0). modules/rlm_unix/rlm_unix.c in FreeRADIUS before 2.2.0, when unix mode is enabled for user authentication, does not properly check the password expiration in /etc/shadow, which allows remote authenticated users to authenticate using an expi

Q: How urgent is CVE-2011-4966?

Priority 39/100. No elevated risk signals yet.

Routine

MEDIUM 6.0UPGRADE

CVE-2011-4966 is a medium-severity flaw (CVSS 6.0) affecting freeradius. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

modules/rlm_unix/rlm_unix.c in FreeRADIUS before 2.2.0, when unix mode is enabled for user authentication, does not properly check the password expiration in /etc/shadow, which allows remote authenticated users to authenticate using an expired password.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.0 (Medium)
EPSS exploit chance	1.4% (top 28%)
CISA exploited list	No
Weakness	CWE-255
Published	2013-03-12
Last modified	2026-06-16

Publisher (CNA): Red Hat, Inc. · Vendor: freeradius

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2013-03-12 23:55 UTCPublished CVE record published
2026-06-16 23:35 UTCUpdated Record last modified

freeradius freeradius UPGRADE

Affected: all versions · <= 2.2.0 · 0.1 · 0.2 · 0.3 · 0.4 · 0.5 · 0.6

Fixed in: newer than 2.2.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy freeradius || rpm -q freeradius || freeradius --version

2. UPGRADE to newer than 2.2.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade freeradius

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade freeradius

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2011-4966?

freeradius: upgrade to newer than 2.2.0. Exact commands for each OS are on this page.

Is CVE-2011-4966 being exploited?

CVE-2011-4966 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2011-4966 affect?

CVE-2011-4966 affects freeradius. Severity is medium (CVSS 6.0). modules/rlm_unix/rlm_unix.c in FreeRADIUS before 2.2.0, when unix mode is enabled for user authentication, does not properly check the password expiration in /etc/shadow, which allows remote authenticated users to authenticate using an expi

How urgent is CVE-2011-4966?

Priority 39/100. No elevated risk signals yet.

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References

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