CVE-2004-2652: The DecodeTCPOptions function in decode.c in Snort before 2.3.0, when printing TCP/IP options using FAST outpu

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HIGH 7.8DOWNGRADE

CVE-2004-2652 is a high-severity flaw (CVSS 7.8) affecting snort. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The DecodeTCPOptions function in decode.c in Snort before 2.3.0, when printing TCP/IP options using FAST output or verbose mode, allows remote attackers to cause a denial of service (crash) via packets with invalid TCP/IP options, which trigger a null dereference.

Why this priority

High severity
EPSS top 4%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	7.8 (High)
EPSS exploit chance	11.2% (top 4%)
CISA exploited list	No
Published	2004-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: sourcefire

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 22:10 UTCUpdated Record last modified

sourcefire snort DOWNGRADE

Affected: 2.1.0 · 2.1.1_rc1 · 2.1.3 · 2.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.1.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.1.0 (Debian / Ubuntu)

apt-cache madison snort sudo apt install snort=<VERSION_BEFORE_2.1.0> sudo apt-mark hold snort

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

dnf --showduplicates list snort sudo dnf downgrade snort-<VERSION_BEFORE_2.1.0> sudo dnf versionlock add snort

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: Snort 2.1/2.2 - DecodeTCPOptions Remote Denial of Service (1)
Exploit-DB: Snort 2.1/2.2 - DecodeTCPOptions Remote Denial of Service (2)

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-2004-2652?

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

Is CVE-2004-2652 being exploited?

CVE-2004-2652 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-2004-2652 affect?

CVE-2004-2652 affects snort. Severity is high (CVSS 7.8). The DecodeTCPOptions function in decode.c in Snort before 2.3.0, when printing TCP/IP options using FAST output or verbose mode, allows remote attackers to cause a denial of service (crash) via packets with invalid TCP/IP options, which tri

How urgent is CVE-2004-2652?

Priority 56/100. High severity; EPSS top 4%: very likely to be exploited; Public exploit reference

Software pages

Suricata and Snort vulnerabilities

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References

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