CERT.be recommends to system administrators to patch your systems immediately if they are running Exim.
CERT.be recommends all System administrators to upgrade their vulnerable Pulse Secure instances to version 9.1R1 and above.
CERT.be recommends administrators to update their Microsoft Windows systems with the latest available patches as soon as possible:
CERT.be recommends all users of Apple iOS devices to upgrade their devices to the latest version of iOS today.
As the time of writing, no patches are yet available. However, Netflix published some mitigations on their GitHub page:
CERT.be recommends systems administrators to patch vulnerable devices after thorough testing.