CVE-1999-0778: Buffer overflow in Xi Graphics Accelerated-X server allows local users to gain root access via a long display

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HIGH 7.2DOWNGRADE

CVE-1999-0778 is a high-severity flaw (CVSS 7.2) affecting accelerated-x server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in Xi Graphics Accelerated-X server allows local users to gain root access via a long display or query parameter.

Why this priority

High severity
Public exploit reference

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

Risk facts

CVSS score	7.2 (High)
EPSS exploit chance	0.7% (top 47%)
CISA exploited list	No
Published	1999-06-25
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: xi graphics

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

Am I affected?

Timeline

1999-06-25 04:00 UTCPublished CVE record published
2026-06-16 21:49 UTCUpdated Record last modified

xi graphics accelerated-x server DOWNGRADE

Affected: 4 · 5

Fixed in: no fixed release known

Safe to downgrade to: a release before 4

1. Check installed version

apt-cache policy accelerated-x-server || rpm -q accelerated-x-server || accelerated-x-server --version

2. No fixed release: DOWNGRADE to a release before 4 (Debian / Ubuntu)

apt-cache madison accelerated-x-server sudo apt install accelerated-x-server=<VERSION_BEFORE_4> sudo apt-mark hold accelerated-x-server

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

dnf --showduplicates list accelerated-x-server sudo dnf downgrade accelerated-x-server-<VERSION_BEFORE_4> sudo dnf versionlock add accelerated-x-server

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: Xi Graphics Accelerated X 4.0.x/5.0 - Local 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-1999-0778?

accelerated-x server: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-1999-0778 being exploited?

CVE-1999-0778 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-1999-0778 affect?

CVE-1999-0778 affects accelerated-x server. Severity is high (CVSS 7.2). Buffer overflow in Xi Graphics Accelerated-X server allows local users to gain root access via a long display or query parameter.

How urgent is CVE-1999-0778?

Priority 43/100. High severity; Public exploit reference

References

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