CVE-2004-0083: Buffer overflow in ReadFontAlias from dirfile.c of XFree86 4.1.0 through 4.3.0 allows local users and remote a

This week

HIGH 10.0DOWNGRADEMITIGATE

CVE-2004-0083 is a high-severity flaw (CVSS 10.0) affecting x11r6, openbsd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in ReadFontAlias from dirfile.c of XFree86 4.1.0 through 4.3.0 allows local users and remote attackers to execute arbitrary code via a font alias file (font.alias) with a long token, a different vulnerability than CVE-2004-0084 and CVE-2004-0106.

Why this priority

Critical severity
EPSS top 2%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	10.0 (High)
EPSS exploit chance	21.2% (top 2%)
CISA exploited list	No
Published	2004-03-03
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: openbsd · xfree86 project

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

Am I affected?

Timeline

2004-03-03 05:00 UTCPublished CVE record published
2026-06-16 22:04 UTCUpdated Record last modified

xfree86 project x11r6 DOWNGRADE

Affected: 4.1.0 · 4.1.11 · 4.1.12 · 4.2.0 · 4.2.1 · 4.3.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.1.0

1. Check installed version

apt-cache policy x11r6 || rpm -q x11r6 || x11r6 --version

2. No fixed release: DOWNGRADE to a release before 4.1.0 (Debian / Ubuntu)

apt-cache madison x11r6 sudo apt install x11r6=<VERSION_BEFORE_4.1.0> sudo apt-mark hold x11r6

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

dnf --showduplicates list x11r6 sudo dnf downgrade x11r6-<VERSION_BEFORE_4.1.0> sudo dnf versionlock add x11r6

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.

openbsd openbsd MITIGATE

Affected: 3.3 · 3.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.3

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: XFree86 4.3 - Font Information File Buffer Overflow

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-2004-0083?

x11r6: downgrade or apply the listed mitigation; openbsd: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2004-0083 being exploited?

CVE-2004-0083 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-2004-0083 affect?

CVE-2004-0083 affects x11r6, openbsd. Severity is high (CVSS 10.0). Buffer overflow in ReadFontAlias from dirfile.c of XFree86 4.1.0 through 4.3.0 allows local users and remote attackers to execute arbitrary code via a font alias file (font.alias) with a long token, a different vulnerability than CVE-2004-0

How urgent is CVE-2004-0083?

Priority 64/100. Critical severity; EPSS top 2%: very likely to be exploited; Public exploit reference

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References

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