---
id: CVE-2025-21726
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  padata: avoid UAF for reorder_work

  Although the previous patch can avoid ps and ps UAF for _do_serial, it
  can not avoid potential UAF issue for reorder_work
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  padata: avoid UAF for reorder_work

  Although the previous patch can avoid ps and ps UAF for _do_serial, it
  can not avoid potential UAF issue for reorder_work. This issu…
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-416
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.4.19, < 5.5'
  - 'linux_kernel >= 5.5.3, < 5.10.235'
  - 'linux_kernel >= 5.11, < 5.15.79'
  - 'linux_kernel >= 5.16, < 6.1.129'
  - 'linux_kernel >= 6.2, < 6.6.76'
  - 'linux_kernel >= 6.7, < 6.12.13'
  - 'linux_kernel >= 6.13, < 6.13.2'
patched:
  - linux_kernel 6.13.2
published: '2025-02-27'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:17:30.520'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-21726'
references:
  - url: 'https://git.kernel.org/stable/c/4c6209efea2208597dbd3e52dc87a0d1a8f2dbe1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6f45ef616775b0ce7889b0f6077fc8d681ab30bc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7000507bb0d2ceb545c0a690e0c707c897d102c2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8ca38d0ca8c3d30dd18d311f1a7ec5cb56972cac'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a54091c24220a4cd847d5b4f36d678edacddbaf0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dd7d37ccf6b11f3d95e797ebe4e9e886d0332600'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f4f1b1169fc3694f9bc3e28c6c68dbbf4cc744c0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-265688.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-784472.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00236
epssPercentile: 0.14463
ingestedAt: '2026-10-15T03:30:12.789Z'
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2025-02-27T17:58:10.478288Z'
---

## Overview

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

padata: avoid UAF for reorder_work

Although the previous patch can avoid ps and ps UAF for _do_serial, it
can not avoid potential UAF issue for reorder_work. This issue can
happen just as below:

crypto_request			crypto_request		crypto_del_alg
padata_do_serial
  ...
  padata_reorder
    // processes all remaining
    // requests then breaks
    while (1) {
      if (!padata)
        break;
      ...
    }

				padata_do_serial
				  // new request added
				  list_add
    // sees the new request
    queue_work(reorder_work)
				  padata_reorder
				    queue_work_on(squeue->work)
...

				<kworker context>
				padata_serial_worker
				// completes new request,
				// no more outstanding
				// requests

							crypto_del_alg
							  // free pd

<kworker context>
invoke_padata_reorder
  // UAF of pd

To avoid UAF for 'reorder_work', get 'pd' ref before put 'reorder_work'
into the 'serial_wq' and put 'pd' ref until the 'serial_wq' finish.

## Affected

- `linux_kernel >= 5.4.19, < 5.5`
- `linux_kernel >= 5.5.3, < 5.10.235`
- `linux_kernel >= 5.11, < 5.15.79`
- `linux_kernel >= 5.16, < 6.1.129`
- `linux_kernel >= 6.2, < 6.6.76`
- `linux_kernel >= 6.7, < 6.12.13`
- `linux_kernel >= 6.13, < 6.13.2`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.13.2`