CVE-2004-0396: Heap-based buffer overflow in CVS 1.11.x up to 1.11.15, and 1.12.x up to 1.12.7, when using the pserver mechan

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HIGH 7.5DOWNGRADE

CVE-2004-0396 is a high-severity flaw (CVSS 7.5) affecting cvs. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Heap-based buffer overflow in CVS 1.11.x up to 1.11.15, and 1.12.x up to 1.12.7, when using the pserver mechanism allows remote attackers to execute arbitrary code via Entry lines.

Why this priority

High severity
EPSS top 1%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	67.5% (top 1%)
CISA exploited list	No
Published	2004-06-14
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: cvs

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

Am I affected?

Timeline

2004-06-14 04:00 UTCPublished CVE record published
2026-06-16 22:05 UTCUpdated Record last modified

cvs cvs DOWNGRADE

Affected: 1.11 · 1.12

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.11

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.11 (Debian / Ubuntu)

apt-cache madison cvs sudo apt install cvs=<VERSION_BEFORE_1.11> sudo apt-mark hold cvs

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

dnf --showduplicates list cvs sudo dnf downgrade cvs-<VERSION_BEFORE_1.11> sudo dnf versionlock add cvs

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: CVS (Linux/FreeBSD) - Remote Entry Line Heap Overflow
Exploit-DB: CVS - Remote Entry Line Root Heap 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-2004-0396?

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

Is CVE-2004-0396 being exploited?

CVE-2004-0396 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-2004-0396 affect?

CVE-2004-0396 affects cvs. Severity is high (CVSS 7.5). Heap-based buffer overflow in CVS 1.11.x up to 1.11.15, and 1.12.x up to 1.12.7, when using the pserver mechanism allows remote attackers to execute arbitrary code via Entry lines.

How urgent is CVE-2004-0396?

Priority 56/100. High severity; EPSS top 1%: very likely to be exploited; Public exploit reference

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References

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