Unspecified vulnerability in IBM WebSphere Application Server (WAS) 5.1 and 6.0.2 before 6.0.2.33 on z/OS, when CSIv2 Identity Assertion is enabled and Enterprise JavaBeans (EJB) interaction occurs between a WAS 6.1 instance and a WAS pre-6.1 instance, allows local users to have an unknown impact via vectors related to (1) use of the wrong subject and (2) multiple CBIND checks.