I am sure you will have heard much about this but, if you haven’t already done so, we recommend that you check in with whoever is responsible for any websites you own (some large providers will have a service status page or similar). Ask if they have applied any PHP security fixes that are needed. It’s likely they will but it is worth checking.
If your website runs services that are critical to your operation, or for those you serve, do you have a contingency plan if the websites were down for 7 days or a month?