SB2026040160 - Improper resource shutdown or release in Linux kernel kvm mmu

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Main Vulnerability Database SB2026040160

SB2026040160 - Improper resource shutdown or release in Linux kernel kvm mmu

Published: April 1, 2026

Security Bulletin ID SB2026040160
Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 security vulnerability.


1) Improper resource shutdown or release (CVE-ID: CVE-2026-23401)

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.


Remediation

Install update from vendor's website.

References