How severe is CVE-2009-0033?

No CVSS score has been assigned to CVE-2009-0033 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2009-0033?

CVE-2009-0033 affects the following packages: org.apache.tomcat:tomcat (Maven), org.apache.tomcat:tomcat (Maven), org.apache.tomcat:tomcat (Maven). Ecosystems affected: Maven.

How do I fix CVE-2009-0033?

The records we use list no patched version of org.apache.tomcat:tomcat for CVE-2009-0033. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

How do I detect CVE-2009-0033 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.tomcat:tomcat, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2009-0033 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2009-0033 actively exploited in the wild?

No public exploit code has been indexed for CVE-2009-0033 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2009-0033?

CVE-2009-0033 has an EPSS (Exploit Prediction Scoring System) score of 10.1%, placing it in the 96th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score warrants monitoring and prompt remediation.

What type of vulnerability is CVE-2009-0033?

CVE-2009-0033 is classified as Improper Input Validation (CWE-20). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2009-0033 published, and has it been updated?

CVE-2009-0033 was published on May 2, 2022 and was last updated on January 23, 2024. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

Not in CISA KEV

CVE-2009-0033 — tomcat

CVE-2009-0033 is a Improper Input Validation vulnerability in org.apache.tomcat:tomcat. EPSS puts its 30-day exploitation probability at 10.1% (96th percentile). The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

Apache Tomcat Denial of Service via Malformed Request Headers

Published

May 2, 2022

Updated

Jan 23, 2024

Affected

3 pkgs

Patched

See advisory

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

10.1%probability of exploitation in next 30 days

Moderate Risk0.00%

Lower risk than most CVEs96th percentile — riskier than 96% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

3 pkgs affected

☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Apache Tomcat 4.1.0 through 4.1.39, 5.5.0 through 5.5.27, and 6.0.0 through 6.0.18, when the Java AJP connector and mod_jk load balancing are used, allows remote attackers to cause a denial of service (application outage) via a crafted request with invalid headers, related to temporary blocking of connectors that have encountered errors, as demonstrated by an error involving a malformed HTTP Host header.

Affected Packages

3 total

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.tomcat:tomcat`	≥ 4.1.0	No fix
☕Maven	`org.apache.tomcat:tomcat`	≥ 5.5.0	No fix
☕Maven	`org.apache.tomcat:tomcat`	≥ 6.0.0	No fix

Affected Products

1 product · 87 configurations

Application

tomcatapache

85 versions

4.1.04.1.14.1.24.1.34.1.44.1.54.1.64.1.74.1.84.1.94.1.104.1.11

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.tomcat:tomcat, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
The records we use list no patched version of org.apache.tomcat:tomcat for CVE-2009-0033. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.
Mitigate without a patch
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

Product	Fixed in	Advisory
JBEWS 1.0 for RHEL 4	`tomcat5-0:5.5.23-1.patch07.19.ep5.el4`	RHSA-2009:1454
JBEWS 1.0 for RHEL 4	`tomcat6-0:6.0.18-11.3.ep5.el4`	RHSA-2009:1506
Red Hat Certificate System 7.3	`ant-0:1.6.5-1jpp_1rh`	RHSA-2010:0602
Red Hat Developer Suite V.3	`tomcat5-0:5.5.23-0jpp_18rh`	RHSA-2009:1563
Red Hat Enterprise Linux 5	`tomcat5-0:5.5.23-0jpp.7.el5_3.2`	RHSA-2009:1164
Red Hat Network Satellite Server v 5.1	`tomcat5-0:5.0.30-0jpp_16rh`	RHSA-2009:1617
Red Hat Network Satellite Server v 5.2	`tomcat5-0:5.5.23-0jpp_18rh`	RHSA-2009:1616
RHAPS Version 2 for RHEL 4	`tomcat5-0:5.5.23-0jpp_4rh.16`	RHSA-2009:1562

Frequently Asked Questions

O3 Security · Impact-Aware SCA

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