CVE 2013-4286
Apache Tomcat before 6.0.39, 7.x before 7.0.47, and 8.x before 8.0.0-RC3, when an HTTP connector or AJP connector is used, does not properly handle certain inconsistent HTTP request headers, which allows remote attackers to trigger incorrect identification of a request's length and conduct request-smuggling attacks via (1) multiple Content-Length headers or (2) a Content-Length header and a "Transfer-Encoding: chunked" header. NOTE: this vulnerability exists because of an incomplete fix for CVE-2005-2090.
See the 
CVE page on Mitre.org
for more details.
