Cybersecurity experts went on high alert today, warning that portions of the Internet could be crippled in the coming days as hackers actively exploit a security hole in a widely used class of computer hardware. On Thursday, San Jose-based Cisco Systems disclosed that nearly all of its Internet router models are vulnerable to a cyberattack that could leave them unable to process Web traffic. The company issued a software fix for the problem and initially said there was no evidence that hackers had figured out how to exploit the security hole. Full Story