In some scenarios hooks created by loaded modules are not being removed when the related module is being unloaded. An attacker may leverage this by forcing the grub2 to call the hooks once the module which registered it was unloaded, leading to a Use-after-free vulnerability. If correctly exploited this vulnerability may result in Arbitrary Code Execution eventually allowing the attacker to by-pass secure boot protections.
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2025:6990 https://access.redhat.com/errata/RHSA-2025:6990