Cisco Flaw Could Threaten Internet

A flaw in software from Cisco Systems Inc., the world’s largest maker of computer-networking gear, may let hackers knock out machines that help run the Internet, the Department of Homeland Security said.

The operating system software for Cisco’s routers and switches has a fault that may let a hacker send data prompting the machines to restart, making them unavailable, the department said. San Jose-based Cisco made a software patch available on its website.