CVE-2004-1866: nstxd in Nstx 1.1 beta3 and earlier allows remote attackers to cause a denial of service (crash) via a large p

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MEDIUM 5.0DOWNGRADE

CVE-2004-1866 is a medium-severity flaw (CVSS 5.0) affecting ip over dns utility. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

nstxd in Nstx 1.1 beta3 and earlier allows remote attackers to cause a denial of service (crash) via a large packet, which triggers a null dereference.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	3.2% (top 12%)
CISA exploited list	No
Published	2004-03-26
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: nstx

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

Am I affected?

Timeline

2004-03-26 05:00 UTCPublished CVE record published
2026-06-16 22:08 UTCUpdated Record last modified

nstx ip over dns utility DOWNGRADE

Affected: 1.0 · 1.1_beta1 · 1.1_beta2 · 1.1_beta3

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

apt-cache policy ip-over-dns-utility || rpm -q ip-over-dns-utility || ip-over-dns-utility --version

2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)

apt-cache madison ip-over-dns-utility sudo apt install ip-over-dns-utility=<VERSION_BEFORE_1.0> sudo apt-mark hold ip-over-dns-utility

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

dnf --showduplicates list ip-over-dns-utility sudo dnf downgrade ip-over-dns-utility-<VERSION_BEFORE_1.0> sudo dnf versionlock add ip-over-dns-utility

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: NSTX 1.0/1.1 - Remote Denial of Service

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-2004-1866?

ip over dns utility: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2004-1866 being exploited?

CVE-2004-1866 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-2004-1866 affect?

CVE-2004-1866 affects ip over dns utility. Severity is medium (CVSS 5.0). nstxd in Nstx 1.1 beta3 and earlier allows remote attackers to cause a denial of service (crash) via a large packet, which triggers a null dereference.

How urgent is CVE-2004-1866?

Priority 45/100. Public exploit reference

References

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