SB2026072123 - Out-of-bounds read in Linux kernel KVM x86 shadow MMU hugepage recovery logic

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Main Vulnerability Database SB2026072123

SB2026072123 - Out-of-bounds read in Linux kernel KVM x86 shadow MMU hugepage recovery logic

Published: July 21, 2026

Security Bulletin ID SB2026072123
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) Out-of-bounds read (CVE-ID: CVE-2026-63807)

CWE-ID: CWE-125 - Out-of-bounds read

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 an out-of-bounds access in the KVM x86 shadow MMU hugepage recovery logic when recovering hugepages for a direct shadow page whose gfn falls outside the target memslot. A local user can create a guest hugepage mapping that extends below the bounds of a memslot to cause a denial of service.

The issue can manifest as a host page fault in kernel mode during hugepage recovery.


Remediation

Install update from vendor's website.

References