Sun Java Runtime Environment (JRE) and SDK 1.4.0_01 and earlier allows untrusted applets to access certain information within trusted applets, which allows attackers to bypass the restrictions of the Java security model.
Java Runtime Environment in Java Development Kit (JDK) 1.2.2_05 and earlier can allow an untrusted Java class to call into a disallowed class, which could allow an attacker to escape the Java sandbox and conduct unauthorized activities.