---
id: CVE-2024-36881
title: 'mm/userfaultfd: reset ptes when close() for wr-protected ones'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  mm/userfaultfd: reset ptes when close() for wr-protected ones

  Userfaultfd unregister includes a step to remove wr-protect bits from all
  the relevant pgtable entries, b…
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'
cvssSource: adp
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= f369b07c861435bd812a9d14493f71b34132ed6f <
    1da0471de653b13c8f63dcd32a23574d683c8310
  - >-
    Linux >= f369b07c861435bd812a9d14493f71b34132ed6f <
    377f3a9a3d032a52325a5b110379a25dd1ab1931
  - >-
    Linux >= f369b07c861435bd812a9d14493f71b34132ed6f <
    8d8b68a5b0c9fb23d37df06bb273ead38fd5a29d
  - >-
    Linux >= f369b07c861435bd812a9d14493f71b34132ed6f <
    c88033efe9a391e72ba6b5df4b01d6e628f4e734
  - Linux 3e2747c3ddfa717697c3cc2aa6ab989e48d6587d
  - Linux >= 5.19.6 < 5.20
  - Linux 6.0
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2024-05-31T18:32:07.483199Z'
published: '2024-05-30'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T12:18:26.092Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2024-36881'
references:
  - url: 'https://git.kernel.org/stable/c/1da0471de653b13c8f63dcd32a23574d683c8310'
  - url: 'https://git.kernel.org/stable/c/377f3a9a3d032a52325a5b110379a25dd1ab1931'
  - url: 'https://git.kernel.org/stable/c/8d8b68a5b0c9fb23d37df06bb273ead38fd5a29d'
  - url: 'https://git.kernel.org/stable/c/c88033efe9a391e72ba6b5df4b01d6e628f4e734'
tags:
  - cve.org
epss: 0.00239
epssPercentile: 0.15028
ingestedAt: '2026-11-03T12:44:28.815Z'
---

## Overview

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

mm/userfaultfd: reset ptes when close() for wr-protected ones

Userfaultfd unregister includes a step to remove wr-protect bits from all
the relevant pgtable entries, but that only covered an explicit
UFFDIO_UNREGISTER ioctl, not a close() on the userfaultfd itself.  Cover
that too.  This fixes a WARN trace.

The only user visible side effect is the user can observe leftover
wr-protect bits even if the user close()ed on an userfaultfd when
releasing the last reference of it.  However hopefully that should be
harmless, and nothing bad should happen even if so.

This change is now more important after the recent page-table-check
patch we merged in mm-unstable (446dd9ad37d0 ("mm/page_table_check:
support userfault wr-protect entries")), as we'll do sanity check on
uffd-wp bits without vma context.  So it's better if we can 100%
guarantee no uffd-wp bit leftovers, to make sure each report will be
valid.

## Affected

- `Linux >= f369b07c861435bd812a9d14493f71b34132ed6f < 1da0471de653b13c8f63dcd32a23574d683c8310`
- `Linux >= f369b07c861435bd812a9d14493f71b34132ed6f < 377f3a9a3d032a52325a5b110379a25dd1ab1931`
- `Linux >= f369b07c861435bd812a9d14493f71b34132ed6f < 8d8b68a5b0c9fb23d37df06bb273ead38fd5a29d`
- `Linux >= f369b07c861435bd812a9d14493f71b34132ed6f < c88033efe9a391e72ba6b5df4b01d6e628f4e734`
- `Linux 3e2747c3ddfa717697c3cc2aa6ab989e48d6587d`
- `Linux >= 5.19.6 < 5.20`
- `Linux 6.0`

## Remediation

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