CVE-2003-0842: Stack-based buffer overflow in mod_gzip_printf for mod_gzip 1.3.26.1a and earlier, and possibly later official

This month

HIGH 7.5DOWNGRADE

CVE-2003-0842 is a high-severity flaw (CVSS 7.5) affecting mod gzip. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Stack-based buffer overflow in mod_gzip_printf for mod_gzip 1.3.26.1a and earlier, and possibly later official versions, when running in debug mode, allows remote attackers to execute arbitrary code via a long filename in a GET request with an "Accept-Encoding: gzip" header.

Why this priority

High severity
Public exploit reference

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	3.6% (top 10%)
CISA exploited list	No
Published	2003-11-17
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: dag apt repository

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

Am I affected?

Timeline

2003-11-17 05:00 UTCPublished CVE record published
2026-06-16 22:03 UTCUpdated Record last modified

dag apt repository mod gzip DOWNGRADE

Affected: 1.3.26.1a

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.3.26.1a

1. Check installed version

apt-cache policy mod-gzip || rpm -q mod-gzip || mod-gzip --version

2. No fixed release: DOWNGRADE to a release before 1.3.26.1a (Debian / Ubuntu)

apt-cache madison mod-gzip sudo apt install mod-gzip=<VERSION_BEFORE_1.3.26.1a> sudo apt-mark hold mod-gzip

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

dnf --showduplicates list mod-gzip sudo dnf downgrade mod-gzip-<VERSION_BEFORE_1.3.26.1a> sudo dnf versionlock add mod-gzip

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: Apache mod_gzip (with debug_mode) 1.2.26.1a - 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-2003-0842?

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

Is CVE-2003-0842 being exploited?

CVE-2003-0842 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-2003-0842 affect?

CVE-2003-0842 affects mod gzip. Severity is high (CVSS 7.5). Stack-based buffer overflow in mod_gzip_printf for mod_gzip 1.3.26.1a and earlier, and possibly later official versions, when running in debug mode, allows remote attackers to execute arbitrary code via a long filename in a GET request with

How urgent is CVE-2003-0842?

Priority 54/100. High severity; Public exploit reference

Related CVEs

CVE-2003-0844 HIGH 7.1 UPGRADE mod_gzip 1.3.26.1a and earlier, and possibly later official versions, when running in debug mode without the A
CVE-2003-0843 HIGH 7.5 UPGRADE Format string vulnerability in mod_gzip_printf for mod_gzip 1.3.26.1a and earlier, and possibly later official

References

← Back to latest CVEs