CVE-2004-2259: vsftpd before 1.2.2, when under heavy load, allows attackers to cause a denial of service (crash) via a SIGCHL

Routine

MEDIUM 5.0DOWNGRADE

CVE-2004-2259 is a medium-severity flaw (CVSS 5.0) affecting vsftpd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

vsftpd before 1.2.2, when under heavy load, allows attackers to cause a denial of service (crash) via a SIGCHLD signal during a malloc or free call, which is not re-entrant.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	2.1% (top 19%)
CISA exploited list	No
Published	2004-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: beasts

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

beasts vsftpd DOWNGRADE

Affected: 1.2.0 · 1.2.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.2.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.2.0 (Debian / Ubuntu)

apt-cache madison vsftpd sudo apt install vsftpd=<VERSION_BEFORE_1.2.0> sudo apt-mark hold vsftpd

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

dnf --showduplicates list vsftpd sudo dnf downgrade vsftpd-<VERSION_BEFORE_1.2.0> sudo dnf versionlock add vsftpd

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-2004-2259?

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

Is CVE-2004-2259 being exploited?

CVE-2004-2259 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-2004-2259 affect?

CVE-2004-2259 affects vsftpd. Severity is medium (CVSS 5.0). vsftpd before 1.2.2, when under heavy load, allows attackers to cause a denial of service (crash) via a SIGCHLD signal during a malloc or free call, which is not re-entrant.

How urgent is CVE-2004-2259?

Priority 38/100. No elevated risk signals yet.

Software pages

vsftpd vulnerabilities

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References

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