Apache Tomcat is a servlet container.
It was found that sending a request without a session identifier to a protected resource could bypass the Cross-Site Request Forgery (CSRF) prevention filter. A remote attacker could use this flaw to perform CSRF attacks against applications that rely on the CSRF prevention filter and do not contain internal mitigation for CSRF. (CVE-2012-4431)
A flaw was found in the way Tomcat handled sendfile operations when using the HTTP NIO (Non-Blocking I/O) connector and HTTPS. A remote attacker could use this flaw to cause a denial of service (infinite loop). The HTTP NIO connector is used by default in JBoss Enterprise Web Server. The Apache Portable Runtime (APR) connector from the Tomcat Native library was not affected by this flaw. (CVE-2012-4534)
Multiple weaknesses were found in the Tomcat DIGEST authentication implementation, effectively reducing the security normally provided by DIGEST authentication. A remote attacker could use these flaws to perform replay attacks in some circumstances. (CVE-2012-5885, CVE-2012-5886, CVE-2012-5887)
A denial of service flaw was found in the way the Tomcat HTTP NIO connector enforced limits on the permitted size of request headers. A remote attacker could use this flaw to trigger an OutOfMemoryError by sending a specially-crafted request with very large headers. The HTTP NIO connector is used by default in JBoss Enterprise Web Server. The APR connector from the Tomcat Native library was not affected by this flaw. (CVE-2012-2733)
Warning: Before applying the update, back up your existing JBoss Enterprise Web Server installation (including all applications and configuration files).
All users of JBoss Enterprise Web Server 2.0.0 as provided from the Red Hat Customer Portal are advised to apply this update.