The new bug, Shellshock, creates a vulnerability in the "Bash" software that's found in Mac and Linux operating systems. Bash controls a computer's command prompt, which is "integral to the running of computers and is behind simple tasks such as opening up an application," CNBC reports.
If hackers were able to detect a security flaw in the Bash software, they could control your computer remotely. With Shellshock, hackers could insert code from remote locations to control your machine.
"The difference in significance is that with Heartbleed... somebody could grab credentials of a user and do what they wanted, but in this case, if somebody is vulnerable, it potentially allows someone to get full system control of a victim's system," David Emm, a senior security research employee at Kaspersky Lab, told CNBC.
The U.S. Computer Emergency Readiness Team, which is a part of the Department of Homeland Security, has urged Mac and Linux users to "patch" or update their operating systems to protect their devices against the Shellshock bug. Meghan DeMaria