---
id: CVE-2025-38083
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net_sched: prio: fix a race in prio_tune()

  Gerrard Tai reported a race condition in PRIO, whenever SFQ perturb timer
  fires at the wrong time.

  The race is as follows:
  …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net_sched: prio: fix a race in prio_tune()

  Gerrard Tai reported a race condition in PRIO, whenever SFQ perturb timer
  fires at the wrong time.

  The race is as follows:
  …
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-362
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.0, < 5.4.295'
  - 'linux_kernel >= 5.5, < 5.10.239'
  - 'linux_kernel >= 5.11, < 5.15.186'
  - 'linux_kernel >= 5.16, < 6.1.142'
  - 'linux_kernel >= 6.2, < 6.6.94'
  - 'linux_kernel >= 6.7, < 6.12.34'
  - 'linux_kernel >= 6.13, < 6.15.3'
  - linux_kernel = 6.16
  - debian_linux = 11.0
patched:
  - linux_kernel 6.15.3
published: '2025-06-20'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:18:25.857'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-38083'
references:
  - url: 'https://git.kernel.org/stable/c/20f68e6a9e41693cb0e55e5b9ebbcb40983a4b8f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/3aaa7c01cf19d9b9bb64b88b65c3a6fd05da2eb4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4483d8b9127591c60c4eb789d6cab953bc4522a9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/46c15c9d0f65c9ba857d63f53264f4b17e8a715f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/53d11560e957d53ee87a0653d258038ce12361b7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/93f9eeb678d4c9c1abf720b3615fa8299a490845'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d35acc1be3480505b5931f17e4ea9b7617fea4d3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e3f6745006dc9423d2b065b90f191cfa11b1b584'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-082556.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00156
epssPercentile: 0.04743
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:47:09.836026Z'
ingestedAt: '2026-10-15T05:52:46.096Z'
---

## Overview

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

net_sched: prio: fix a race in prio_tune()

Gerrard Tai reported a race condition in PRIO, whenever SFQ perturb timer
fires at the wrong time.

The race is as follows:

CPU 0                                 CPU 1
[1]: lock root
[2]: qdisc_tree_flush_backlog()
[3]: unlock root
 |
 |                                    [5]: lock root
 |                                    [6]: rehash
 |                                    [7]: qdisc_tree_reduce_backlog()
 |
[4]: qdisc_put()

This can be abused to underflow a parent's qlen.

Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog()
should fix the race, because all packets will be purged from the qdisc
before releasing the lock.

## Affected

- `linux_kernel >= 5.0, < 5.4.295`
- `linux_kernel >= 5.5, < 5.10.239`
- `linux_kernel >= 5.11, < 5.15.186`
- `linux_kernel >= 5.16, < 6.1.142`
- `linux_kernel >= 6.2, < 6.6.94`
- `linux_kernel >= 6.7, < 6.12.34`
- `linux_kernel >= 6.13, < 6.15.3`
- `linux_kernel = 6.16`
- `debian_linux = 11.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.15.3`