CVE-2006-3739: Integer overflow in the CIDAFM function in X.Org 6.8.2 and XFree86 X server allows local users to execute arbi

Routine

HIGH 7.2DOWNGRADEMITIGATE

CVE-2006-3739 is a high-severity flaw (CVSS 7.2) affecting x.org, xfree86 x. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Integer overflow in the CIDAFM function in X.Org 6.8.2 and XFree86 X server allows local users to execute arbitrary code via crafted Adobe Font Metrics (AFM) files with a modified number of character metrics (StartCharMetrics), which leads to a heap-based buffer overflow.

Why this priority

High severity

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

Risk facts

CVSS score	7.2 (High)
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Published	2006-09-13
Last modified	2026-06-16

Publisher (CNA): Red Hat, Inc. · Vendor: x.org · xfree86 project

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

Am I affected?

Timeline

2006-09-13 01:07 UTCPublished CVE record published
2026-06-16 22:27 UTCUpdated Record last modified

x.org x.org DOWNGRADE

Affected: 6.8.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.8.2

1. Check installed version

apt-cache policy x.org || rpm -q x.org || x.org --version

2. No fixed release: DOWNGRADE to a release before 6.8.2 (Debian / Ubuntu)

apt-cache madison x.org sudo apt install x.org=<VERSION_BEFORE_6.8.2> sudo apt-mark hold x.org

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

dnf --showduplicates list x.org sudo dnf downgrade x.org-<VERSION_BEFORE_6.8.2> sudo dnf versionlock add x.org

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.

xfree86 project xfree86 x MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy xfree86-x || rpm -q xfree86-x || xfree86-x --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

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-2006-3739?

x.org: downgrade or apply the listed mitigation; xfree86 x: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2006-3739 being exploited?

CVE-2006-3739 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-2006-3739 affect?

CVE-2006-3739 affects x.org, xfree86 x. Severity is high (CVSS 7.2). Integer overflow in the CIDAFM function in X.Org 6.8.2 and XFree86 X server allows local users to execute arbitrary code via crafted Adobe Font Metrics (AFM) files with a modified number of character metrics (StartCharMetrics), which leads

How urgent is CVE-2006-3739?

Priority 37/100. High severity

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References

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