Apache Tomcat is a servlet container. It was found that when an application used FORM authentication, along with another component that calls request.setUserPrincipal before the call to FormAuthenticator#authenticate , it was possible to bypass the security constraint checks in the FORM authenticator by appending "/j_security_check" to the end of a URL. A remote attacker with an authenticated session on an affected application could use this flaw to circumvent authorization controls, and thereby access resources not permitted by the roles associated with their authenticated session. 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. Users of Tomcat should upgrade to these updated packages, which correct these issues. Tomcat must be restarted for this update to take effect.