Apache Tomcat is a servlet container for the Java Servlet and JavaServer Pages (JSP) technologies.
It was discovered that Apache Tomcat did not limit the length of chunk sizes when using chunked transfer encoding. A remote attacker could use this flaw to perform a denial of service attack against Tomcat by streaming an unlimited quantity of data, leading to excessive consumption of server resources. (CVE-2014-0075)
It was found that Apache Tomcat did not check for overflowing values when parsing request content length headers. A remote attacker could use this flaw to perform an HTTP request smuggling attack on a Tomcat server located behind a reverse proxy that processed the content length header correctly. (CVE-2014-0099)
It was found that the org.apache.catalina.servlets.DefaultServlet implementation in Apache Tomcat allowed the definition of XML External Entities (XXEs) in provided XSLTs. A malicious application could use this to circumvent intended security restrictions to disclose sensitive information. (CVE-2014-0096)
The CVE-2014-0075 issue was discovered by David Jorm of Red Hat Product Security.
This update also fixes the following bugs:
The patch that resolved the CVE-2014-0050 issue contained redundant code. This update removes the redundant code. (BZ#1094528)
The patch that resolved the CVE-2013-4322 issue contained an invalid check that triggered a java.io.EOFException while reading trailer headers for chunked requests. This update fixes the check and the aforementioned exception is no longer triggered in the described scenario. (BZ#1095602)
All Tomcat 6 users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. Tomcat must be restarted for this update to take effect.