CVE-2004-0259: The check_referer() function in Formmail.php 5.0 and earlier allows remote attackers to bypass access restrict

This month

HIGH 9.3DOWNGRADE

CVE-2004-0259 is a high-severity flaw (CVSS 9.3) affecting formmail.php. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The check_referer() function in Formmail.php 5.0 and earlier allows remote attackers to bypass access restrictions via an empty or spoofed HTTP Referer, as demonstrated using an application on the same web server that contains a cross-site scripting (XSS) issue.

Why this priority

Critical severity

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

Risk facts

CVSS score	9.3 (High)
EPSS exploit chance	2.1% (top 19%)
CISA exploited list	No
Published	2004-11-23
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: joe lumbroso acks

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

Am I affected?

Timeline

2004-11-23 05:00 UTCPublished CVE record published
2026-06-16 22:05 UTCUpdated Record last modified

joe lumbroso acks formmail.php DOWNGRADE

Affected: 2.0 · 5.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0

1. Check installed version

apt-cache policy formmail.php || rpm -q formmail.php || formmail.php --version

2. No fixed release: DOWNGRADE to a release before 2.0 (Debian / Ubuntu)

apt-cache madison formmail.php sudo apt install formmail.php=<VERSION_BEFORE_2.0> sudo apt-mark hold formmail.php

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

dnf --showduplicates list formmail.php sudo dnf downgrade formmail.php-<VERSION_BEFORE_2.0> sudo dnf versionlock add formmail.php

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-2004-0259?

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

Is CVE-2004-0259 being exploited?

CVE-2004-0259 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-2004-0259 affect?

CVE-2004-0259 affects formmail.php. Severity is high (CVSS 9.3). The check_referer() function in Formmail.php 5.0 and earlier allows remote attackers to bypass access restrictions via an empty or spoofed HTTP Referer, as demonstrated using an application on the same web server that contains a cross-site

How urgent is CVE-2004-0259?

Priority 53/100. Critical severity

Software pages

PHP vulnerabilities

References

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