According to http://tomcat.apache.org/security-5.html Fixed in Apache Tomcat 5.5.13, 5.0.HEAD Directory listing CVE-2006-3835 This is expected behaviour when directory listings are enabled. The semicolon (;) is the separator for path parameters so inserting one before a file name changes the request into a request for a directory with a path parameter. If directory listings are enabled, a directory listing will be shown. In response to this and other directory listing issues, directory listings were changed to be disabled by default. Affects: 5.0.0-5.5.30, 5.5.0-5.5.12
Note that there's no actual fix in Tomcat 5.5.17 (as the problem is not Tomcat related, but is caused by mod_jk). It is simply that in that release directory listing is disabled by default, while in previous versions it is enabled by default which mitigates this issue. Therefore the severity of this issue for a given Tomcat package will depend on how Tomcat is packaged and the defaults used.
Advisory text: "Directory listings were enabled by default in Tomcat. This could lead to a minor information leak if sensitive information is stored unprotected under the document root and the administrator did not disable directory listings (CVE-2007-0450)"
This issue has been addressed in following products: Red Hat Certificate System 7.3 Via RHSA-2010:0602 https://rhn.redhat.com/errata/RHSA-2010-0602.html
Please see https://access.redhat.com/security/cve/CVE-2006-3835 for a list of other products that contain this fix.