Unspecified vulnerability in Java Runtime Environment in Java JDK and JRE 5.0 Update 3 and earlier allows remote attackers to escape the Java sandbox and access arbitrary files or execute arbitrary applications via unknown attack vectors involving untrusted Java applets.

Java Runtime Environment (JRE) Bytecode Verifier allows remote attackers to escape the Java sandbox and execute commands via an applet containing an illegal cast operation, as seen in (1) Microsoft VM build 3802 and earlier as used in Internet Explorer 4.x and 5.x, (2) Netscape 6.2.1 and earlier, and possibly other implementations that use vulnerable versions of SDK or JDK, aka a variant of the "Virtual Machine Verifier" vulnerability.