CVE-2000-0594: BitchX IRC client does not properly cleanse an untrusted format string, which allows remote attackers to cause

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MEDIUM 5.0WATCHLISTDOWNGRADEDOWNGRADEMITIGATE

CVE-2000-0594 is a medium-severity flaw (CVSS 5.0) affecting openlinux desktop, openlinux ebuilder, openlinux edesktop. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

BitchX IRC client does not properly cleanse an untrusted format string, which allows remote attackers to cause a denial of service via an invite to a channel whose name includes special formatting characters.

Why this priority

EPSS top 4%: very likely to be exploited
Public exploit reference
On your watchlist

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	9.9% (top 4%)
CISA exploited list	No
Published	2000-07-04
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: caldera · freebsd · mandrakesoft

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

Am I affected?

Timeline

2000-07-04 04:00 UTCPublished CVE record published
2026-06-16 21:52 UTCUpdated Record last modified

caldera openlinux desktop DOWNGRADE

Affected: 2.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.3

1. Check installed version

apt-cache policy openlinux-desktop || rpm -q openlinux-desktop || openlinux-desktop --version

2. No fixed release: DOWNGRADE to a release before 2.3 (Debian / Ubuntu)

apt-cache madison openlinux-desktop sudo apt install openlinux-desktop=<VERSION_BEFORE_2.3> sudo apt-mark hold openlinux-desktop

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

dnf --showduplicates list openlinux-desktop sudo dnf downgrade openlinux-desktop-<VERSION_BEFORE_2.3> sudo dnf versionlock add openlinux-desktop

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.

caldera openlinux ebuilder DOWNGRADE

Affected: 2.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.3

1. Check installed version

apt-cache policy openlinux-ebuilder || rpm -q openlinux-ebuilder || openlinux-ebuilder --version

2. No fixed release: DOWNGRADE to a release before 2.3 (Debian / Ubuntu)

apt-cache madison openlinux-ebuilder sudo apt install openlinux-ebuilder=<VERSION_BEFORE_2.3> sudo apt-mark hold openlinux-ebuilder

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

dnf --showduplicates list openlinux-ebuilder sudo dnf downgrade openlinux-ebuilder-<VERSION_BEFORE_2.3> sudo dnf versionlock add openlinux-ebuilder

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.

caldera openlinux edesktop MITIGATE

Affected: 2.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.4

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.

caldera openlinux eserver MITIGATE

Affected: 2.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.3

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.

freebsd freebsd MITIGATE

Affected: 3.5 · 4.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.5

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.

mandrakesoft mandrake linux MITIGATE

Affected: 2007

Fixed in: no fixed release known

Safe to downgrade to: a release before 2007

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: BitchX IRC Client 75p1/75p3/1.0 c16 - '/INVITE' 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-2000-0594?

openlinux desktop: downgrade or apply the listed mitigation; openlinux ebuilder: downgrade or apply the listed mitigation; openlinux edesktop: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2000-0594 being exploited?

CVE-2000-0594 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-2000-0594 affect?

CVE-2000-0594 affects openlinux desktop, openlinux ebuilder, openlinux edesktop. Severity is medium (CVSS 5.0). BitchX IRC client does not properly cleanse an untrusted format string, which allows remote attackers to cause a denial of service via an invite to a channel whose name includes special formatting characters.

How urgent is CVE-2000-0594?

Priority 51/100. EPSS top 4%: very likely to be exploited; Public exploit reference; On your watchlist

Related CVEs

CVE-2001-0181 HIGH 10.0 DOWNGRADE MITIGATE Format string vulnerability in the error logging code of DHCP server and client in Caldera Linux allows remote
CVE-2001-0139 LOW 1.2 DOWNGRADE DOWNGRADE inn 2.2.3 allows local users to overwrite arbitrary files via a symlink attack in some configurations.

References

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