CVE-2004-2303: MTools Mformat before 3.9.9, when installed setuid root, creates files with world-readable and world-writable

Routine

LOW 3.6DOWNGRADE

CVE-2004-2303 is a low-severity flaw (CVSS 3.6) affecting mformat. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

MTools Mformat before 3.9.9, when installed setuid root, creates files with world-readable and world-writable permissions, which allows local users to read and overwrite files.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	3.6 (Low)
EPSS exploit chance	0.6% (top 50%)
CISA exploited list	No
Published	2004-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: mtools

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

mtools mformat DOWNGRADE

Affected: 3.9.1 · 3.9.2 · 3.9.3 · 3.9.4 · 3.9.5 · 3.9.6 · 3.9.7 · 3.9.8

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.9.1

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 3.9.1 (Debian / Ubuntu)

apt-cache madison mformat sudo apt install mformat=<VERSION_BEFORE_3.9.1> sudo apt-mark hold mformat

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

dnf --showduplicates list mformat sudo dnf downgrade mformat-<VERSION_BEFORE_3.9.1> sudo dnf versionlock add mformat

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.

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: MTools 3.9.x - 'MFormat' Local Privilege Escalation

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-2004-2303?

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

Is CVE-2004-2303 being exploited?

CVE-2004-2303 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-2004-2303 affect?

CVE-2004-2303 affects mformat. Severity is low (CVSS 3.6). MTools Mformat before 3.9.9, when installed setuid root, creates files with world-readable and world-writable permissions, which allows local users to read and overwrite files.

How urgent is CVE-2004-2303?

Priority 30/100. Public exploit reference

References

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