CVE-2026-46290

Technical Description

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

x86/efi: Fix graceful fault handling after FPU softirq changes

Since commit d02198550423 ("x86/fpu: Improve crypto performance by

making kernel-mode FPU reliably usable in softirqs"), kernel_fpu_begin()

calls fpregs_lock() which uses local_bh_disable() instead of the

previous preempt_disable(). This sets SOFTIRQ_OFFSET in preempt_count

during the entire EFI runtime service call, causing in_interrupt() to

return true in normal task context.

The graceful page fault handler efi_crash_gracefully_on_page_fault()

uses in_interrupt() to bail out for faults in real interrupt context.

With SOFTIRQ_OFFSET now set, the handler always bails out, leaving EFI

firmware page faults unhandled. This escalates to die() which also sees

in_interrupt() as true and calls panic("Fatal exception in interrupt"),

resulting in a hard system freeze. On systems with buggy firmware that

triggers page faults during EFI runtime calls (e.g., accessi

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. 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.

Affected Products

References