---
id: CVE-2026-43045
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  mshv: Fix error handling in mshv_region_pin

  The current error handling has two issues:

  First, pin_user_pages_fast() can return a short pin count (less than
  requested …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  mshv: Fix error handling in mshv_region_pin

  The current error handling has two issues:

  First, pin_user_pages_fast() can return a short pin count (less than
  requested …
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 6.15, < 6.19.12'
  - linux_kernel = 7.0
patched:
  - linux_kernel 6.19.12
published: '2026-05-01'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T11:17:29.957'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-43045'
references:
  - url: 'https://git.kernel.org/stable/c/a7d149152bc5a9119854331c57be35ad31fdf5cc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c0e296f257671ba10249630fe58026f29e4804d9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d14847cb7f65d419e43451d416a1f50c09a5f3be'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00143
epssPercentile: 0.03222
ingestedAt: '2026-10-15T11:00:41.711Z'
---

## Overview

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

mshv: Fix error handling in mshv_region_pin

The current error handling has two issues:

First, pin_user_pages_fast() can return a short pin count (less than
requested but greater than zero) when it cannot pin all requested pages.
This is treated as success, leading to partially pinned regions being
used, which causes memory corruption.

Second, when an error occurs mid-loop, already pinned pages from the
current batch are not properly accounted for before calling
mshv_region_invalidate_pages(), causing a page reference leak.

Treat short pins as errors and fix partial batch accounting before
cleanup.

## Affected

- `linux_kernel >= 6.15, < 6.19.12`
- `linux_kernel = 7.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.19.12`