Poisoning writes an arbitrary value to freed pages, so any modification or reference to that page after being freed or before being initialized will be detected and prevented.
This prevents many types of use-after-free vulnerabilities at little performance cost. This also prevents data leaks and detects corrupted memory.
Check
Verify that GRUB 2 is configured to enable page poisoning to mitigate use-after-free vulnerabilities.
Check that the current GRUB 2 configuration has page poisoning enabled with the following command: