A security update has been issued by Sun which is expected to patch vulnerabilities in its Java Web Start application. It is a highly critical security flaw which was detected in Java Web Start JDK and JRE 5.0 Update 11 along with Java Web Start in SDK and on Windows version JRE 1.4.2_13 and earlier.

This flaw could allow access to untrusted applications for overwriting any file written by user running the application. It could then be used for execution of arbitrary code with the permission of user running the untrusted application.

As a result Sun has issued two security updates, the first one is for Java Web Start in JDK and JRE 5.0 Update 12 or later and the second update is for Java Web Start in SDK and JRE 1.4.2_14 or later. Click here and here for the patches.