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.
Weaknesses in this category are related to the design and implementation of data confidentiality and integrity. Frequently these deal with the use of encoding techniques, encryption libraries, and hashing algorithms. The weaknesses in this category could lead to a degradation of the quality data if they are not addressed.