CVE-2001-0838: Format string vulnerability in Network Solutions Rwhoisd 1.5.x allows remote attackers to execute arbitrary co

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HIGH 7.5DOWNGRADE

CVE-2001-0838 is a high-severity flaw (CVSS 7.5) affecting rwhoisd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Format string vulnerability in Network Solutions Rwhoisd 1.5.x allows remote attackers to execute arbitrary code via format string specifiers in the -soa command.

Why this priority

High severity
EPSS top 6%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	7.0% (top 6%)
CISA exploited list	No
Published	2001-12-06
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: network solutions

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

Am I affected?

Timeline

2001-12-06 05:00 UTCPublished CVE record published
2026-06-16 21:55 UTCUpdated Record last modified

network solutions rwhoisd DOWNGRADE

Affected: 1.5.x

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.5.x

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.5.x (Debian / Ubuntu)

apt-cache madison rwhoisd sudo apt install rwhoisd=<VERSION_BEFORE_1.5.x> sudo apt-mark hold rwhoisd

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

dnf --showduplicates list rwhoisd sudo dnf downgrade rwhoisd-<VERSION_BEFORE_1.5.x> sudo dnf versionlock add rwhoisd

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: NSI Rwhoisd 1.5 - Remote Format String

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-2001-0838?

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

Is CVE-2001-0838 being exploited?

CVE-2001-0838 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-2001-0838 affect?

CVE-2001-0838 affects rwhoisd. Severity is high (CVSS 7.5). Format string vulnerability in Network Solutions Rwhoisd 1.5.x allows remote attackers to execute arbitrary code via format string specifiers in the -soa command.

How urgent is CVE-2001-0838?

Priority 55/100. High severity; EPSS top 6%: very likely to be exploited; Public exploit reference

Related CVEs

CVE-2001-0913 HIGH 7.5 DOWNGRADE Format string vulnerability in Network Solutions Rwhoisd 1.5.7.2 and earlier, when using syslog, allows remote

References

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