The US Food and Drug Administration (FDA) is conducting a probe into allegations by short-selling company Muddy Waters and cybersecurity firm MedSec Holdings that pacemakers and defibrillators manufactured by St. Jude Medical have cybersecurity defects and can be exploited by hackers, reports Reuters.

"Regardless of the way a vulnerability comes to our attention, we take those allegations very, very seriously," said FDA official Suzanne Schwartz.

According to the news agency, the charge by Muddy Waters goes against FDA draft guidelines that researcheres should report security vulnerablities to the manufacturer. 

St. Jude has sued the companies and rejected their claims of security flaws.

Read more on Reuters.