---
id: CVE-2022-50630
title: 'mm: hugetlb: fix UAF in hugetlb_handle_userfault'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  mm: hugetlb: fix UAF in hugetlb_handle_userfault

  The vma_lock and hugetlb_fault_mutex are dropped before handling userfault
  and reacquire them again after handle_userf…
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'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1a1aad8a9b7bd34f60cdf98cd7915f00ae892c45 <
    45c33966759ea1b4040c08dacda99ef623c0ca29
  - >-
    Linux >= 1a1aad8a9b7bd34f60cdf98cd7915f00ae892c45 <
    0db2efb3bff879566f05341d94c3de00ac95c4cc
  - >-
    Linux >= 1a1aad8a9b7bd34f60cdf98cd7915f00ae892c45 <
    dd691973f67b2800a97db723b1ff6f07fdcf7f5a
  - >-
    Linux >= 1a1aad8a9b7bd34f60cdf98cd7915f00ae892c45 <
    78504bcedb2f1bbfb353b4d233c24d641c4dda33
  - >-
    Linux >= 1a1aad8a9b7bd34f60cdf98cd7915f00ae892c45 <
    958f32ce832ba781ac20e11bb2d12a9352ea28fc
  - Linux 4.11
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:31:42.914433Z'
published: '2025-12-08'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T21:41:21.996Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2022-50630'
references:
  - url: 'https://git.kernel.org/stable/c/45c33966759ea1b4040c08dacda99ef623c0ca29'
  - url: 'https://git.kernel.org/stable/c/0db2efb3bff879566f05341d94c3de00ac95c4cc'
  - url: 'https://git.kernel.org/stable/c/dd691973f67b2800a97db723b1ff6f07fdcf7f5a'
  - url: 'https://git.kernel.org/stable/c/78504bcedb2f1bbfb353b4d233c24d641c4dda33'
  - url: 'https://git.kernel.org/stable/c/958f32ce832ba781ac20e11bb2d12a9352ea28fc'
tags:
  - cve.org
epss: 0.00153
epssPercentile: 0.04002
ingestedAt: '2026-10-15T22:48:25.377Z'
---

## Overview

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

mm: hugetlb: fix UAF in hugetlb_handle_userfault

The vma_lock and hugetlb_fault_mutex are dropped before handling userfault
and reacquire them again after handle_userfault(), but reacquire the
vma_lock could lead to UAF[1,2] due to the following race,

hugetlb_fault
  hugetlb_no_page
    /*unlock vma_lock */
    hugetlb_handle_userfault
      handle_userfault
        /* unlock mm->mmap_lock*/
                                           vm_mmap_pgoff
                                             do_mmap
                                               mmap_region
                                                 munmap_vma_range
                                                   /* clean old vma */
        /* lock vma_lock again  <--- UAF */
    /* unlock vma_lock */

Since the vma_lock will unlock immediately after
hugetlb_handle_userfault(), let's drop the unneeded lock and unlock in
hugetlb_handle_userfault() to fix the issue.

[1] https://lore.kernel.org/linux-mm/000000000000d5e00a05e834962e@google.com/
[2] https://lore.kernel.org/linux-mm/20220921014457.1668-1-liuzixian4@huawei.com/

## Affected

- `Linux >= 1a1aad8a9b7bd34f60cdf98cd7915f00ae892c45 < 45c33966759ea1b4040c08dacda99ef623c0ca29`
- `Linux >= 1a1aad8a9b7bd34f60cdf98cd7915f00ae892c45 < 0db2efb3bff879566f05341d94c3de00ac95c4cc`
- `Linux >= 1a1aad8a9b7bd34f60cdf98cd7915f00ae892c45 < dd691973f67b2800a97db723b1ff6f07fdcf7f5a`
- `Linux >= 1a1aad8a9b7bd34f60cdf98cd7915f00ae892c45 < 78504bcedb2f1bbfb353b4d233c24d641c4dda33`
- `Linux >= 1a1aad8a9b7bd34f60cdf98cd7915f00ae892c45 < 958f32ce832ba781ac20e11bb2d12a9352ea28fc`
- `Linux 4.11`

## Remediation

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