CVE-2000-0623: Buffer overflow in O'Reilly WebSite Professional web server 2.4 and earlier allows remote attackers to execute

This week

HIGH 10.0DOWNGRADE

CVE-2000-0623 is a high-severity flaw (CVSS 10.0) affecting website professional. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in O'Reilly WebSite Professional web server 2.4 and earlier allows remote attackers to execute arbitrary commands via a long GET request or Referrer header.

Why this priority

Critical severity
EPSS top 7%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	10.0 (High)
EPSS exploit chance	5.3% (top 7%)
CISA exploited list	No
Published	2000-07-17
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: oreilly

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

Am I affected?

Timeline

2000-07-17 04:00 UTCPublished CVE record published
2026-06-16 21:52 UTCUpdated Record last modified

oreilly website professional DOWNGRADE

Affected: 2.3.18 · 2.4 · 2.4.9

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.3.18

1. Check installed version

apt-cache policy website-professional || rpm -q website-professional || website-professional --version

2. No fixed release: DOWNGRADE to a release before 2.3.18 (Debian / Ubuntu)

apt-cache madison website-professional sudo apt install website-professional=<VERSION_BEFORE_2.3.18> sudo apt-mark hold website-professional

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

dnf --showduplicates list website-professional sudo dnf downgrade website-professional-<VERSION_BEFORE_2.3.18> sudo dnf versionlock add website-professional

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.

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-2000-0623?

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

Is CVE-2000-0623 being exploited?

CVE-2000-0623 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-2000-0623 affect?

CVE-2000-0623 affects website professional. Severity is high (CVSS 10.0). Buffer overflow in O'Reilly WebSite Professional web server 2.4 and earlier allows remote attackers to execute arbitrary commands via a long GET request or Referrer header.

How urgent is CVE-2000-0623?

Priority 63/100. Critical severity; EPSS top 7%: very likely to be exploited; Public exploit reference

Related CVEs

CVE-2001-0626 HIGH 7.5 UPGRADE O'Reilly Website Professional 2.5.4 and earlier allows remote attackers to determine the physical path to the
CVE-2000-0622 HIGH 10.0 DOWNGRADE Buffer overflow in Webfind CGI program in O'Reilly WebSite Professional web server 2.x allows remote attackers

References

← Back to latest CVEs