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Vulnerability record · CVE-2009-0033 · published 5 June 2009

CVE-2009-0033: Apache tomcat improper input validation vulnerability

Apache · Tomcat

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.

5.0 CVSS 2.0 Medium EPSS 10% · top 4.5% CWE-20 · Improper input validation
5.0CVSS 2.0 base score
10%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
94References
16 Jun 2026Last modified by NVD

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.

AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://jvn.jp/en/jp/JVN87272440/index.html
http://lists.apple.com/archives/security-announce/2010//Mar/msg00001.html
http://lists.opensuse.org/opensuse-security-announce/2009-07/msg00002.html
http://marc.info/?l=bugtraq&m=127420533226623&w=2
http://marc.info/?l=bugtraq&m=129070310906557&w=2
http://marc.info/?l=bugtraq&m=133469267822771&w=2
http://marc.info/?l=bugtraq&m=136485229118404&w=2
http://secunia.com/advisories/35326 Vendor Advisory
http://secunia.com/advisories/35344 Vendor Advisory
http://secunia.com/advisories/35685
http://secunia.com/advisories/35788
http://secunia.com/advisories/37460
http://secunia.com/advisories/42368
http://securitytracker.com/id?1022331
http://sunsolve.sun.com/search/document.do?assetkey=1-26-263529-1
http://support.apple.com/kb/HT4077
http://svn.apache.org/viewvc?rev=742915&view=rev PatchVendor Advisory
http://svn.apache.org/viewvc?rev=781362&view=rev PatchVendor Advisory
http://tomcat.apache.org/security-4.html PatchVendor Advisory
http://tomcat.apache.org/security-5.html PatchVendor Advisory
http://tomcat.apache.org/security-6.html PatchVendor Advisory
http://www.debian.org/security/2011/dsa-2207
http://www.mandriva.com/security/advisories?name=MDVSA-2009:136
http://www.mandriva.com/security/advisories?name=MDVSA-2009:138
http://www.mandriva.com/security/advisories?name=MDVSA-2010:176
http://www.securityfocus.com/archive/1/504044/100/0/threaded
http://www.securityfocus.com/archive/1/507985/100/0/threaded
http://www.securityfocus.com/bid/35193 Patch
http://www.vmware.com/security/advisories/VMSA-2009-0016.html
http://www.vupen.com/english/advisories/2009/1496 PatchVendor Advisory
http://www.vupen.com/english/advisories/2009/1856
http://www.vupen.com/english/advisories/2009/3316
http://www.vupen.com/english/advisories/2010/3056
https://exchange.xforce.ibmcloud.com/vulnerabilities/50928
https://lists.apache.org/thread.html/06cfb634bc7bf37af7d8f760f118018746ad8efbd519c4b789ac9c2e%40%3Cdev.tomcat.apache.org
https://lists.apache.org/thread.html/29dc6c2b625789e70a9c4756b5a327e6547273ff8bde7e0327af48c5%40%3Cdev.tomcat.apache.org
https://lists.apache.org/thread.html/8dcaf7c3894d66cb717646ea1504ea6e300021c85bb4e677dc16b1aa%40%3Cdev.tomcat.apache.org
https://lists.apache.org/thread.html/c62b0e3a7bf23342352a5810c640a94b6db69957c5c19db507004d74%40%3Cdev.tomcat.apache.org
https://lists.apache.org/thread.html/r3aacc40356defc3f248aa504b1e48e819dd0471a0a83349080c6bcbf%40%3Cdev.tomcat.apache.or
https://lists.apache.org/thread.html/r584a714f141eff7b1c358d4679288177bd4ca4558e9999d15867d4b5%40%3Cdev.tomcat.apache.or

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Source: NIST National Vulnerability Database (record CVE-2009-0033), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.