Java 1.7 -- security manager bypass

US-CERT reports:

Oracle Java Runtime Environment (JRE) 1.7 contains a vulnerability that may allow an applet to call setSecurityManager in a way that allows setting of arbitrary permissions.

By leveraging the public, privileged getField() function, an untrusted Java applet can escalate its privileges by calling the setSecurityManager() function to allow full privileges, without requiring code signing.

This vulnerability is being actively exploited in the wild, and exploit code is publicly available.

[source]

This exploit does not only affect Java applets, but every piece of software that relies on the Java Security Manager for sandboxing executable code is affected: malicious code can totally disable Security Manager.