Meltdown and Sepctre are a codename for various vulnerabilities of basically every Intel processor, which allows a malicious attacker to gain unrestricted access to the computer's memory, so every copy/paste command, every keyboard stroke, etc.
Medical devices are known to be slow with updates, which means that such devices might be vulnerable for quite a while. A successful attack would allow the attacker to gain access to images or potentially any medical data that is being processed on a medical workstation. This exposes the medical institutions and other providers to the potential of huge fines and law suites.
See Also
- https://meltdownattack.com/
- https://support.apple.com/en-us/HT208394