It's already being called one of the biggest security threats the Internet has ever seen.
Two thirds of all websites are affected and could have exposed your sensitive account information, such as passwords and credit card numbers over the past two years. It's all because of an encryption flaw called the Heartbleed bug.
"It's a pretty big deal that they are able to get that information," Kyle Rodgers of Green Eggs and Ram said.
The Heartbleed bug has affected many popular websites and services, ones you probably use every day including Gmail, Facebook, maybe even your bank.
The threat was discovered Monday by security experts and not through a known attack.
"So it's not a group of hackers who figured this out; it was an IT security company that was testing it and disclosed it," Rodgers said.
Rodgers says so far, there's been no indication of any huge thefts of data across the country, but it's still early.
Because the bug affects two thirds of all internet web sites, experts say you should change your passwords, but not just yet.
"My advice is to hold off for a couple of days, limit your online activity, especially when it comes to purchasing things or accessing personal finance, privacy related stuff like that until the problem gets solved and then change your password on everything," Rodgers said.
Some Internet companies that were vulnerable to the bug have already updated their servers with a security patch to fix the issue. But even so that doesn't guarantee your information wasn't already compromised.