Java Web Start (JWS) and Java Plug-in with Sun JDK and JRE 6 Update 10 and earlier; JDK and JRE 5.0 Update 16 and earlier; and SDK and JRE 1.4.2_18 and earlier allows remote attackers to make unauthorized network connections and hijack HTTP sessions via a crafted file that validates as both a GIF and a Java JAR file, aka "GIFAR" and CR 6707535.