CVE-2026-64183

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

efi: Allocate runtime workqueue before ACPI init

Since commit

5894cf571e14 ("acpi/prmt: Use EFI runtime sandbox to invoke PRM handlers")

ACPI PRM calls are delegated to a workqueue which runs in a kernel

thread, making it easier to detect and mitigate faulting memory accesses

performed by the firmware.

Rafael reports that such PRM accesses may occur before efisubsys_init()

executes, which is where the workqueue is allocated, leading to NULL

pointer dereferences. Since acpi_init() [which triggers the early PRM

accesses] executes as a subsys_initcall() as well, and has its own

dependencies that may be sensitive to initcall ordering, deferring

acpi_init() is not an option.

So instead, split off the workqueue allocation into its own postcore

initcall, as this is the only missing piece to allow EFI runtime calls

to be made. This ensures that EFI runtime call (including PRM calls) are

accessible to all code running a

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References