---
id: CVE-2026-89755
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  mm/migrate_device: clear stale mapping after freeing swapcache

  __migrate_device_pages() reads the folio mapping before calling
  folio_free_swap()
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  mm/migrate_device: clear stale mapping after freeing swapcache

  __migrate_device_pages() reads the folio mapping before calling
  folio_free_swap().  When folio_free_swap…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-825
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= df263d9a7dffee94ca5391120ee3b0587efa07f1 <
    4fa91f7bbc4135240b67daac03fc17d9e180a331
  - >-
    Linux >= df263d9a7dffee94ca5391120ee3b0587efa07f1 <
    8ffedc6573a665cdc31ebe47eae7b32b78d0df83
  - >-
    Linux >= df263d9a7dffee94ca5391120ee3b0587efa07f1 <
    34a00895d032a414830d41106a09329ae6c251b6
  - Linux 6.6
published: '2026-09-11'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T14:17:26.320'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89755'
references:
  - url: 'https://git.kernel.org/stable/c/34a00895d032a414830d41106a09329ae6c251b6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4fa91f7bbc4135240b67daac03fc17d9e180a331'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8ffedc6573a665cdc31ebe47eae7b32b78d0df83'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89755.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89755'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532241'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89755'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89755'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89755.mbox
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00173
epssPercentile: 0.059
scores:
  nvd: 7.8
  cna: 7.8
  vendor: 7
ingestedAt: '2026-09-14T15:23:07.472Z'
---

## Overview

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

mm/migrate_device: clear stale mapping after freeing swapcache

__migrate_device_pages() reads the folio mapping before calling
folio_free_swap().  When folio_free_swap() succeeds, the folio is removed
from the swap cache, but the saved mapping still points to swap_space.

Passing the stale mapping to folio_migrate_mapping() makes it use the
mapped-folio path for a folio that is no longer in swapcache.  It can then
operate on swap_space.i_pages with invalid reference accounting,
eventually triggering a folio reference count BUG.

After a successful split, nr still contains the number of pages in the
original large folio, although each resulting page is now a separate
order-0 folio.  Reset nr to 1 so each split folio is processed separately,
including its own swapcache removal and mapping lookup.

Refresh the saved mapping after folio_free_swap() so the current folio
state is used during migration.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89755.json)