Description
Apache Tomcat before 5.5.35, 6.x before 6.0.35, and 7.x before 7.0.23 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 6.0 | tomcat6 | 6.0.35-1+squeeze2 | DSA-2401-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | tomcat6 +8 | 6.0.24-36.el6_2 | RHSA-2012:0475 |
| RHEL 5 | tomcat5 +10 | 5.5.23-0jpp.31.el5_8 | RHSA-2012:0474 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat JBoss Web Server 1 | tomcat5 +12 | 5.5.33-27_patch_07.ep5.el5 | RHSA-2012:0680 |
| Red Hat JBoss Web Server 1 | tomcat6 +9 | 6.0.32-24_patch_07.ep5.el5 | RHSA-2012:0682 |
| Red Hat JBoss Web Platform 5 | jbossweb +4 | 2.1.12-3_patch_03.2.ep5.el5 | RHSA-2012:0076 |
| Red Hat JBoss EAP 5 | jbossweb +4 | 2.1.12-3_patch_03.2.ep5.el4 | RHSA-2012:0074 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Metasploit 1 module
-
Hashtable Collisions
auxiliary/dos/http/hashcollision_dos
Exploit-DB 1
- MyBulletinBoard (MyBB) 1.1.5 - 'CLIENT-IP' SQL Injection EDB-2012 · webapps · Jul 15, 2006 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Maven | org.apache.tomcat:tomcat | >= 5.5.0, < 5.5.35 | 5.5.35 | GHSA-wr3m-gw98-mc3j |
| Maven | org.apache.tomcat:tomcat | >= 6.0.0, < 6.0.35 | 6.0.35 | GHSA-wr3m-gw98-mc3j |
| Maven | org.apache.tomcat:tomcat | >= 7.0.0, < 7.0.23 | 7.0.23 | GHSA-wr3m-gw98-mc3j |
Advisories 7
- RHSA-2012:0682 Red Hat Security Advisory: tomcat6 security and bug fix update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2012:0680 Red Hat Security Advisory: tomcat5 security and bug fix update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2012:0474 Red Hat Security Advisory: tomcat5 security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2012:0475 Red Hat Security Advisory: tomcat6 security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2012:0076 Red Hat Security Advisory: jbossweb security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2012:0074 Red Hat Security Advisory: jbossweb security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- DSA-2401-1 tomcat6 - several Debian Security (DSA / DLA) · Mar 9, 2026
References
- https://github.com/FireFart/HashCollision-DOS-POC/blob/master/HashtablePOC.py
- DSA-2401 vendor-advisory
- http://www.nruns.com/_downloads/advisory28122011.pdf
- RHSA-2012:0325 vendor-advisory
- HPSBUX02860 vendor-advisory
- RHSA-2012:0078 vendor-advisory
- 51200 vdb-entry
- https://bugzilla.redhat.com/show_bug.cgi?id=750521
- 48791 third-party-advisory
- oval:org.mitre.oval:def:18886 vdb-entry signature
- http://tomcat.apache.org/tomcat-7.0-doc/changelog.html
- RHSA-2012:0075 vendor-advisory
- RHSA-2012:0074 vendor-advisory
- 48549 third-party-advisory
- RHSA-2012:0089 vendor-advisory
- 54971 third-party-advisory
- 48790 third-party-advisory
- 55115 third-party-advisory
- VU#903934 third-party-advisory
- [announce] 20111228 [SECURITY] Apache Tomcat and the hashtable collision DoS vulnerability mailing-list
- SSRT100771 vendor-advisory
- SSRT100728 vendor-advisory
- RHSA-2012:0406 vendor-advisory
- RHSA-2012:0076 vendor-advisory
- RHSA-2012:0077 vendor-advisory
- http://www.ocert.org/advisories/ocert-2011-003.html