An issue with mod_jk 1.2.26, and possibly older versions, allows one user to see another user's information due to missing logic where faulty clients set Content-Length without providing data, or if a user submits too many times very fast. The relevant changelog entry in mod_jk 1.2.27 that corrects the issue is: "AJP13: Always send initial POST packet even if the client disconnected after sending request but before providing POST data. In that case or in case the client broke the connection in a middle of read send an zero size packet informing container about broken client connection. (mturk)" from http://tomcat.apache.org/connectors-doc/miscellaneous/changelog.html
This issue affects 1.2.0 through to 1.2.26 and is fixed in revision 702540: http://svn.eu.apache.org/viewvc?view=rev&revision=702540
This is public now: http://marc.info/?l=tomcat-dev&m=123913700700879
This issue has been addressed in following products: Red Hat Web Application Stack for RHEL 5 Via RHSA-2009:0446 https://rhn.redhat.com/errata/RHSA-2009-0446.html
This issue has been addressed in following products: RHAPS Version 2 for RHEL 4 Via RHSA-2009:1087 https://rhn.redhat.com/errata/RHSA-2009-1087.html
This issue has been addressed in following products: Red Hat Network Satellite Server v 5.1 Red Hat Network Satellite Server v 5.2 Via RHSA-2009:1618 https://rhn.redhat.com/errata/RHSA-2009-1618.html
We will not be issuing a fix for this flaw in Red Hat Network Satellite Server v 5.0. That version is only supported for high priority security fixes, which this is not.