The FDA is issuing a major recall, saying that half a million people’s pacemakers could be hacked. The Food and Drug Administration discovered flaws that could allow a hacker to change the settings or even turn it off.

“This access could be used to modify programming commands to the implanted pacemaker, which could result in inpatient harm from rapid battery depletion or administration of inappropriate pacing,” the warning reads.

So far, there have not been any reports of unauthorized access to these implanted devices, but they need to be updated with new security software. Patients will not need a new surgery to do this.

The devices that are affected are the following St. Jude Medical pacemaker and CRT-P devices:

• Accent
• Anthem
• Accent MRI
• Accent ST
• Assurity
• Allure

Officials say this communication does not apply to any implantable cardiac defibrillators (ICDs) or to cardiac resynchronization ICDs (CRT-Ds).