CVE-2003-0209: Integer overflow in the TCP stream reassembly module (stream4) for Snort 2.0 and earlier allows remote attacke

This week

HIGH 10.0DOWNGRADEDOWNGRADE

CVE-2003-0209 is a high-severity flaw (CVSS 10.0) affecting smoothwall, snort. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Integer overflow in the TCP stream reassembly module (stream4) for Snort 2.0 and earlier allows remote attackers to execute arbitrary code via large sequence numbers in packets, which enable a heap-based buffer overflow.

Why this priority

Critical 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	10.0 (High)
EPSS exploit chance	38.6% (top 1%)
CISA exploited list	No
Published	2003-05-05
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: smoothwall · sourcefire

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

Am I affected?

Timeline

2003-05-05 04:00 UTCPublished CVE record published
2026-06-16 22:01 UTCUpdated Record last modified

smoothwall smoothwall DOWNGRADE

Affected: 2.0_beta_4

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0_beta_4

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.0_beta_4 (Debian / Ubuntu)

apt-cache madison smoothwall sudo apt install smoothwall=<VERSION_BEFORE_2.0_beta_4> sudo apt-mark hold smoothwall

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

dnf --showduplicates list smoothwall sudo dnf downgrade smoothwall-<VERSION_BEFORE_2.0_beta_4> sudo dnf versionlock add smoothwall

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.

sourcefire snort DOWNGRADE

Affected: 1.8 · 1.8.1 · 1.8.2 · 1.8.3 · 1.8.4 · 1.8.5 · 1.8.6 · 1.8.7

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.8

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.8 (Debian / Ubuntu)

apt-cache madison snort sudo apt install snort=<VERSION_BEFORE_1.8> sudo apt-mark hold snort

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

dnf --showduplicates list snort sudo dnf downgrade snort-<VERSION_BEFORE_1.8> 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 1.9.1 - 'p7snort191.sh' Remote Command Execution

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-2003-0209?

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

Is CVE-2003-0209 being exploited?

CVE-2003-0209 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-2003-0209 affect?

CVE-2003-0209 affects smoothwall, snort. Severity is high (CVSS 10.0). Integer overflow in the TCP stream reassembly module (stream4) for Snort 2.0 and earlier allows remote attackers to execute arbitrary code via large sequence numbers in packets, which enable a heap-based buffer overflow.

How urgent is CVE-2003-0209?

Priority 65/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference

Software pages

Suricata and Snort vulnerabilities

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References

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