CVE-2004-2523: Format string vulnerability in the msg command (cat_message function in msg.c) in OpenFTPD 0.30.2 and earlier

Q: How do I fix CVE-2004-2523?

openftpd ftp server: upgrade to newer than 0.30.2. Exact commands for each OS are on this page.

Q: Is CVE-2004-2523 being exploited?

CVE-2004-2523 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2004-2523 affect?

CVE-2004-2523 affects openftpd ftp server. Severity is medium (CVSS 6.5). Format string vulnerability in the msg command (cat_message function in msg.c) in OpenFTPD 0.30.2 and earlier allows remote authenticated users to execute arbitrary code via format string specifiers in the message argument.

Q: How urgent is CVE-2004-2523?

Priority 51/100. EPSS top 7%: very likely to be exploited; Public exploit reference

This month

MEDIUM 6.5UPGRADE

CVE-2004-2523 is a medium-severity flaw (CVSS 6.5) affecting openftpd ftp server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Format string vulnerability in the msg command (cat_message function in msg.c) in OpenFTPD 0.30.2 and earlier allows remote authenticated users to execute arbitrary code via format string specifiers in the message argument.

Why this priority

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

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
EPSS exploit chance	5.4% (top 7%)
CISA exploited list	No
Published	2004-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: openftpd

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

Am I affected?

Timeline

2004-12-31 05:00 UTCPublished CVE record published
2026-06-16 22:09 UTCUpdated Record last modified

openftpd openftpd ftp server UPGRADE

Affected: <= 0.30.2 · 0.29.4 · 0.30 · 0.30.1

Fixed in: newer than 0.30.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy openftpd-ftp-server || rpm -q openftpd-ftp-server || openftpd-ftp-server --version

2. UPGRADE to newer than 0.30.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade openftpd-ftp-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade openftpd-ftp-server

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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: OpenFTPd 0.30.1 - message system Remote Shell
Exploit-DB: OpenFTPd 0.30.2 - Remote Overflow

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-2004-2523?

openftpd ftp server: upgrade to newer than 0.30.2. Exact commands for each OS are on this page.

Is CVE-2004-2523 being exploited?

CVE-2004-2523 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-2004-2523 affect?

CVE-2004-2523 affects openftpd ftp server. Severity is medium (CVSS 6.5). Format string vulnerability in the msg command (cat_message function in msg.c) in OpenFTPD 0.30.2 and earlier allows remote authenticated users to execute arbitrary code via format string specifiers in the message argument.

How urgent is CVE-2004-2523?

Priority 51/100. EPSS top 7%: very likely to be exploited; Public exploit reference

References

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