Improper resource shutdown or release in Linux kernel - CVE-2026-23401
Published: April 1, 2026
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper handling of SPTE updates in KVM MMU when installing emulated MMIO SPTEs. A local user can trigger a page fault after host userspace modifies guest memory mappings to switch from memslot to emulated MMIO, leading to an attempt to mark an already present SPTE as MMIO, which results in a kernel warning and potential guest crash. A local user can send a specially crafted request to cause a denial of service.
The issue arises when KVM fails to drop the existing shadow-present SPTE before installing an MMIO SPTE, resulting in inconsistent MMU state and triggering a kernel warning that can crash the guest.