HP have released a notice about how to fix this issue: reinstall the affected drivers via HP Easy Start or, Apple Software Update or downloading drivers from HP’s website. (I did
I tried the lattersecond.) I got an error saying the driver is damaged and can’t be installed. But the driver download from HP at https://support.hp.com/gb-en/drivers worked.
https://eclecticlight.co/2020/10/26/what-happened-with-security-updates-and-hp-printer-software/