SB2026080477 - Improper Initialization in Linux kernel kvm mmu



SB2026080477 - Improper Initialization in Linux kernel kvm mmu

Published: August 4, 2026

Security Bulletin ID SB2026080477
CSH 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 vulnerability.


1) Improper Initialization (CVE-ID: CVE-2026-64561)

CWE-ID: CWE-665 - Improper Initialization

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper state management in the KVM x86 shadow MMU page fault handling code when processing stale page faults after reclaiming shadow pages. A local user can trigger page faults that lead KVM to map memory into an invalid root to cause a denial of service.

The issue occurs when reclaiming shadow pages invalidates an in-use root, causing child shadow pages created during map or fetch operations to inherit an invalid role and violate the invariant that invalid shadow pages must not appear on the list of active MMU pages.


Remediation

Install update from vendor's website.