Improper Authentication in Apache MyFaces
shared/util/StateUtils.java in Apache MyFaces 1.1.x before 1.1.8, 1.2.x before 1.2.9, and 2.0.x before 2.0.1 uses an encrypted View State without a Message Authentication Code (MAC), which makes it easier for remote attackers to perform successful modifications of the View State via a padding oracle attack.