Multiple unspecified vulnerabilities in Sun Java Runtime Environment (JRE) in JDK and JRE 6 before Update 7, JDK and JRE 5.0 before Update 16, SDK and JRE 1.4.x before 1.4.2_18, and SDK and JRE 1.3.x before 1.3.1_23 allow remote attackers to violate the security model for an applet's outbound connections by connecting to localhost services running on the machine that loaded the applet.
The Sun Java Plugin capability in Java 2 Runtime Environment (JRE) 1.4.2_01, 1.4.2_04, and possibly earlier versions, does not properly restrict access between Javascript and Java applets during data transfer, which allows remote attackers to load unsafe classes and execute arbitrary code by using the reflection API to access private Java packages.