The US Department of Homeland Security warned Thursday that a flaw in Java software is so dangerous that people should stop using it.
"This vulnerability is being attacked in the wild, and is reported to be incorporated into exploit kits," the department's Computer Emergency Readiness Team said in a notice on its website.
"We are currently unaware of a practical solution to this problem."
The recommended solution was to disable Java, which typically runs as a plug-in program in web browsers.
Java is distributed by business software powerhouse Oracle and is popular because it lets developers create websites in code that can be accessed regardless of a computer's operating system.
Java was created by Sun Microsystems, which was purchased by Northern California-based Oracle.
Hackers who get people to visit booby-trapped websites can exploit the Java vulnerability to execute code on computers, according to security firms that have backed up CERT's warning.