---
id: CVE-2026-64244
title: 'drivers/base/memory: set mem->altmap after successful device registration'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  drivers/base/memory: set mem->altmap after successful device registration

  If __add_memory_block() fails at xa_store() (under memory pressure for
  example), device_unreg…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 <
    802e113cf120df7208e4c7e604950a85e87120a8
  - >-
    Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 <
    22dc0d042f02ce82aa61422ea5f232628bfd9e9c
  - >-
    Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 <
    6c25bf4e44a2b6a14332f952bba0974521f5b72d
  - >-
    Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 <
    bc3dd82a0ffd488bb902f4c69c3d28fd4088d973
  - >-
    Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 <
    059ac6252a63edf1cea79bf30bd860a8c264b62c
  - >-
    Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 <
    a2b8d7827f48ee54a686cb80e4a1d0ff954ec42a
  - Linux 6.6
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:32:52.837206Z'
published: '2026-07-24'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:34:31.181Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-64244'
references:
  - url: 'https://git.kernel.org/stable/c/802e113cf120df7208e4c7e604950a85e87120a8'
  - url: 'https://git.kernel.org/stable/c/22dc0d042f02ce82aa61422ea5f232628bfd9e9c'
  - url: 'https://git.kernel.org/stable/c/6c25bf4e44a2b6a14332f952bba0974521f5b72d'
  - url: 'https://git.kernel.org/stable/c/bc3dd82a0ffd488bb902f4c69c3d28fd4088d973'
  - url: 'https://git.kernel.org/stable/c/059ac6252a63edf1cea79bf30bd860a8c264b62c'
  - url: 'https://git.kernel.org/stable/c/a2b8d7827f48ee54a686cb80e4a1d0ff954ec42a'
tags:
  - cve.org
epss: 0.00115
epssPercentile: 0.01532
ingestedAt: '2026-11-06T16:57:43.216Z'
---

## Overview

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

drivers/base/memory: set mem->altmap after successful device registration

If __add_memory_block() fails at xa_store() (under memory pressure for
example), device_unregister() is called, which eventually triggers
memory_block_release() with mem->altmap still set, causing a
WARN_ON(mem->altmap).  This was triggered by modifying virtio-mem driver.

Fix this by delaying the assignment of mem->altmap until after
__add_memory_block() has succeeded.

## Affected

- `Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 < 802e113cf120df7208e4c7e604950a85e87120a8`
- `Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 < 22dc0d042f02ce82aa61422ea5f232628bfd9e9c`
- `Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 < 6c25bf4e44a2b6a14332f952bba0974521f5b72d`
- `Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 < bc3dd82a0ffd488bb902f4c69c3d28fd4088d973`
- `Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 < 059ac6252a63edf1cea79bf30bd860a8c264b62c`
- `Linux >= 1a8c64e110435e44e71bcd50a75663174b575f22 < a2b8d7827f48ee54a686cb80e4a1d0ff954ec42a`
- `Linux 6.6`

## Remediation

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