Homeland Security’s US Computer Emergency Readiness Team advises to uninstall QuickTime from all Windows machines as Apple is ending support. This means Apple will no longer be providing security updates, and as we all know that leaves the threat of security holes wide open. As prevalent as Ransomware and Zero-Day Malware is these days, it is absolutely necessary to update and patch any security holes that arise.
QuickTime for Windows currently has critical security vulnerabilities, and Apple will not be pushing out anymore security updates for Windows. Because of this immediate threat, CBM Technology will be removing QuickTime from all of our devices as well as our Managed Anti-Virus Clients and higher. It is highly recommended that you do as well! This is the only mitigation available.
Read more from the US-CERT article here.