Launchpad.net

CVE 2009-2671

The SOCKS proxy implementation in Sun Java Runtime Environment (JRE) in JDK and JRE 6 before Update 15, and JDK and JRE 5.0 before Update 20, allows remote attackers to discover the username of the account that invoked an untrusted (1) applet or (2) Java Web Start application via unspecified vectors.

See the CVE page on Mitre.org for more details.