---
id: CVE-2023-3609
title: >-
  A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32
  component can be exploited to achieve local privilege escalation.




  If tcf_change_indev() fails, u32_set_parms() will immediately return an error
  after incrementing…
summary: >-
  A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32
  component can be exploited to achieve local privilege escalation.




  If tcf_change_indev() fails, u32_set_parms() will immediately return an error
  after incrementing…
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 >= 4.14, < 4.14.322'
  - 'linux_kernel >= 4.15, < 4.19.291'
  - 'linux_kernel >= 4.20, < 5.4.248'
  - 'linux_kernel >= 5.5, < 5.10.185'
  - 'linux_kernel >= 5.11, < 5.15.118'
  - 'linux_kernel >= 5.16, < 6.1.35'
  - 'linux_kernel >= 6.2, < 6.3.9'
  - linux_kernel = 6.4
  - debian_linux = 10.0
  - debian_linux = 11.0
patched:
  - linux_kernel 6.3.9
published: '2023-07-21'
updated: '2026-09-11'
sourceUpdated: '2026-09-11T16:16:30.007'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2023-3609'
references:
  - url: >-
      http://packetstormsecurity.com/files/175072/Kernel-Live-Patch-Security-Notice-LSN-0098-1.html
    label: cve-coordination@google.com
  - url: >-
      http://packetstormsecurity.com/files/175963/Kernel-Live-Patch-Security-Notice-LSN-0099-1.html
    label: cve-coordination@google.com
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=04c55383fa5689357bcdd2c8036725a55ed632bc
    label: cve-coordination@google.com
  - url: 'https://kernel.dance/04c55383fa5689357bcdd2c8036725a55ed632bc'
    label: cve-coordination@google.com
  - url: 'https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html'
    label: cve-coordination@google.com
  - url: 'https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html'
    label: cve-coordination@google.com
  - url: 'https://security.netapp.com/advisory/ntap-20230818-0005/'
    label: cve-coordination@google.com
  - url: 'https://www.debian.org/security/2023/dsa-5480'
    label: cve-coordination@google.com
  - url: >-
      http://packetstormsecurity.com/files/175072/Kernel-Live-Patch-Security-Notice-LSN-0098-1.html
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      http://packetstormsecurity.com/files/175963/Kernel-Live-Patch-Security-Notice-LSN-0099-1.html
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=04c55383fa5689357bcdd2c8036725a55ed632bc
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://kernel.dance/04c55383fa5689357bcdd2c8036725a55ed632bc'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.netapp.com/advisory/ntap-20230818-0005/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.debian.org/security/2023/dsa-5480'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - exploit-available
epss: 0.00454
epssPercentile: 0.38762
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/Jturnxd/CVE-2023-3609'
  checkedAt: '2026-09-24T07:52:49.967Z'
exploitAvailable: true
ingestedAt: '2026-07-30T17:54:54.534Z'
---

## Overview

A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component can be exploited to achieve local privilege escalation.



If tcf_change_indev() fails, u32_set_parms() will immediately return an error after incrementing or decrementing the reference counter in tcf_bind_filter(). If an attacker can control the reference counter and set it to zero, they can cause the reference to be freed, leading to a use-after-free vulnerability.



We recommend upgrading past commit 04c55383fa5689357bcdd2c8036725a55ed632bc.

## Affected

- `linux_kernel >= 4.14, < 4.14.322`
- `linux_kernel >= 4.15, < 4.19.291`
- `linux_kernel >= 4.20, < 5.4.248`
- `linux_kernel >= 5.5, < 5.10.185`
- `linux_kernel >= 5.11, < 5.15.118`
- `linux_kernel >= 5.16, < 6.1.35`
- `linux_kernel >= 6.2, < 6.3.9`
- `linux_kernel = 6.4`
- `debian_linux = 10.0`
- `debian_linux = 11.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.3.9`