An issue with modjk 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 modjk 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
Absolute path traversal vulnerability in Apache Tomcat 4.0.0 through 4.0.6, 4.1.0, 5.0.0, 5.5.0 through 5.5.25, and 6.0.0 through 6.0.14, under certain configurations, allows remote authenticated users to read arbitrary files via a WebDAV write request that specifies an entity with a SYSTEM tag.
Multiple cross-site scripting (XSS) vulnerabilities in the (1) Manager and (2) Host Manager web applications in Apache Tomcat 4.0.0 through 4.0.6, 4.1.0 through 4.1.36, 5.0.0 through 5.0.30, 5.5.0 through 5.5.24, and 6.0.0 through 6.0.13 allow remote authenticated users to inject arbitrary web script or HTML via a parameter name to manager/html/upload, and other unspecified vectors.
The AJP connector in Apache Tomcat 4.0.1 through 4.0.6 and 4.1.0 through 4.1.36, as used in Hitachi Cosminexus Application Server and standalone, does not properly handle when a connection is broken before request body data is sent in a POST request, which can lead to an information leak when "unsuitable request body data" is used for a different request, possibly related to Java Servlet pages.