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.

readObject in (1) Java Runtime Environment (JRE) and (2) Software Development Kit (SDK) 1.4.0 through 1.4.2_05 allows remote attackers to cause a denial of service (JVM unresponsive) via crafted serialized data.

Sun Java Runtime Environment (JRE) 1.x before 1.4.2_11 and 1.5.x before 1.5.0_06, and as used in multiple web browsers, allows remote attackers to cause a denial of service (application crash) via deeply nested object arrays, which are not properly handled by the garbage collector and trigger invalid memory accesses.