CoreResponseStateManager in Apache MyFaces Trinidad 1.0.0 through 1.0.13, 1.2.x before 1.2.15, 2.0.x before 2.0.2, and 2.1.x before 2.1.2 might allow attackers to conduct deserialization attacks via a crafted serialized view state string.
Trinidad s CoreResponseStateManager both reads and writes view state strings using ObjectInputStream/ObjectOutputStream directly. By doing so, Trinidad bypasses the view state security features provided by the JSF implementations - ie. the view state is not encrypted and is not MAC ed.
Trinidad s CoreResponseStateManager will blindly deserialize untrusted view state strings, which makes Trinidad-based applications vulnerable to deserialization attacks.