CVE-2000-0976: Buffer overflow in xlib in XFree 3.3.x possibly allows local users to execute arbitrary commands via a long DI

Routine

MEDIUM 4.6DOWNGRADE

CVE-2000-0976 is a medium-severity flaw (CVSS 4.6) affecting xlib. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in xlib in XFree 3.3.x possibly allows local users to execute arbitrary commands via a long DISPLAY environment variable or a -display command line parameter.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	4.6 (Medium)
EPSS exploit chance	1.0% (top 38%)
CISA exploited list	No
Published	2000-12-19
Last modified	2026-09-23

Publisher (CNA): MITRE · Vendor: xfree86 project

Last updated 2026-09-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2000-12-19 05:00 UTCPublished CVE record published
2026-09-23 10:10 UTCUpdated Record last modified

xfree86 project xlib DOWNGRADE

Affected: 3.3x

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.3x

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 3.3x (Debian / Ubuntu)

apt-cache madison xlib sudo apt install xlib=<VERSION_BEFORE_3.3x> sudo apt-mark hold xlib

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

dnf --showduplicates list xlib sudo dnf downgrade xlib-<VERSION_BEFORE_3.3x> sudo dnf versionlock add xlib

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.

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 3.3.5/3.3.6 - Xlib Display 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-2000-0976?

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

Is CVE-2000-0976 being exploited?

CVE-2000-0976 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-2000-0976 affect?

CVE-2000-0976 affects xlib. Severity is medium (CVSS 4.6). Buffer overflow in xlib in XFree 3.3.x possibly allows local users to execute arbitrary commands via a long DISPLAY environment variable or a -display command line parameter.

How urgent is CVE-2000-0976?

Priority 37/100. Public exploit reference

References

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