A severe security breach was discovered in the current Java version 7 and the German Federal Office for Information Security (BSI) suggests deactivating the Java plug-in in the browser's settings if it's not needed. If users visit manipulated websites, hackers can channel damaging software into a Windows computer.
And hackers have already used the weak spot for attacks. Those who do not need Java should de-install the runtime environment entirely. It's not known when the security breach will be filled.