(RHSA-2009:1506) Important: tomcat6 security update

Apache Tomcat is a servlet container for the Java Servlet and JavaServer
Pages (JSP) technologies.

It was discovered that request dispatchers did not properly normalize user
requests that have trailing query strings, allowing remote attackers to
send specially-crafted requests that would cause an information leak.
(CVE-2008-5515)

A flaw was found in the way the Tomcat AJP (Apache JServ Protocol)
connector processes AJP connections. An attacker could use this flaw to
send specially-crafted requests that would cause a temporary denial of
service. (CVE-2009-0033)

It was discovered that the error checking methods of certain authentication
classes did not have sufficient error checking, allowing remote attackers
to enumerate (via brute force methods) usernames registered with
applications running on Tomcat when FORM-based authentication was used.
(CVE-2009-0580)

It was discovered that web applications containing their own XML parsers
could replace the XML parser Tomcat uses to parse configuration files. A
malicious web application running on a Tomcat instance could read or,
potentially, modify the configuration and XML-based data of other web
applications deployed on the same Tomcat instance. (CVE-2009-0783)

Users of Tomcat should upgrade to these updated packages, which contain
backported patches to resolve these issues. Tomcat must be restarted for
this update to take effect.