The set of vulnerabilities is dubbed PHP2Shell and disclosure is scheduled for 14:00 UTC with attacks expected to follow soon after.
It is adviced to take offline every non-vital services until the patch has been installed (or the Docker image has been updated with a patched version of PHP)
Update: fix is out https://www.php.net/archive/2026.php#2026-10-21-5
depends. do you want to deal with a simple patch in 24 hours or do you want to rebuild an entire legacy system from nothing (assuming you don’t take proper backups)?