CVE-2012-3547: Stack-based buffer overflow in the cbtls_verify function in FreeRADIUS 2.1.10 through 2.1.12, when using TLS-b

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MEDIUM 6.8DOWNGRADE

CVE-2012-3547 is a medium-severity flaw (CVSS 6.8) affecting freeradius. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Stack-based buffer overflow in the cbtls_verify function in FreeRADIUS 2.1.10 through 2.1.12, when using TLS-based EAP methods, allows remote attackers to cause a denial of service (server crash) and possibly execute arbitrary code via a long "not after" timestamp in a client certificate.

Why this priority

EPSS top 7%: very likely to be exploited

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.8 (Medium)
EPSS exploit chance	5.7% (top 7%)
CISA exploited list	No
Weakness	CWE-119
Published	2012-09-18
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

2012-09-18 17:55 UTCPublished CVE record published
2026-06-16 23:43 UTCUpdated Record last modified

freeradius freeradius DOWNGRADE

Affected: 2.1.10 · 2.1.11 · 2.1.12

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.1.10

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.1.10 (Debian / Ubuntu)

apt-cache madison freeradius sudo apt install freeradius=<VERSION_BEFORE_2.1.10> sudo apt-mark hold freeradius

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list freeradius sudo dnf downgrade freeradius-<VERSION_BEFORE_2.1.10> sudo dnf versionlock add freeradius

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2012-3547?

freeradius: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2012-3547 being exploited?

CVE-2012-3547 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-2012-3547 affect?

CVE-2012-3547 affects freeradius. Severity is medium (CVSS 6.8). Stack-based buffer overflow in the cbtls_verify function in FreeRADIUS 2.1.10 through 2.1.12, when using TLS-based EAP methods, allows remote attackers to cause a denial of service (server crash) and possibly execute arbitrary code via a lo

How urgent is CVE-2012-3547?

Priority 47/100. EPSS top 7%: very likely to be exploited

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References

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