---
id: CVE-2023-53566
title: >-
  In the Linux kernel, the following vulnerability has been resolved:


  netfilter: nft_set_rbtree: fix null deref on element insertion


  There is no guarantee that rb_prev() will not return NULL in
  nft_rbtree_gc_elem():


  general protection f…
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  netfilter: nft_set_rbtree: fix null deref on element insertion


  There is no guarantee that rb_prev() will not return NULL in
  nft_rbtree_gc_elem():


  general protection f…
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-476
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.10.166, < 5.10.181'
  - 'linux_kernel >= 5.15.91, < 5.15.113'
  - 'linux_kernel >= 6.1.9, < 6.1.30'
  - 'linux_kernel >= 6.2.1, < 6.3.4'
  - linux_kernel = 6.2
  - linux_kernel = 6.4
patched:
  - linux_kernel 6.3.4
published: '2025-10-04'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:17:43.140'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2023-53566'
references:
  - url: 'https://git.kernel.org/stable/c/3fa13203b6d90cc3a33af47b058739f92ab82eef'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/61ae320a29b0540c16931816299eb86bf2b66c08'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/899aa5638568abf5d69de7a7bb95e4615157375b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a337706c1fb35aac3f26b48aca80421bdbe1d33a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a836be60a3aabcedcd9c79f545d409ace1f20ba6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b76db53ee8802ee5683f8cb401d7e2ec6f9b3d56'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ec5caa765f7f6960011c919c9aeb1467940421f6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00153
epssPercentile: 0.04426
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:35:38.094456Z'
ingestedAt: '2026-10-15T22:48:25.409Z'
---

## Overview

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

netfilter: nft_set_rbtree: fix null deref on element insertion

There is no guarantee that rb_prev() will not return NULL in nft_rbtree_gc_elem():

general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
 nft_add_set_elem+0x14b0/0x2990
  nf_tables_newsetelem+0x528/0xb30

Furthermore, there is a possible use-after-free while iterating,
'node' can be free'd so we need to cache the next value to use.

## Affected

- `linux_kernel >= 5.10.166, < 5.10.181`
- `linux_kernel >= 5.15.91, < 5.15.113`
- `linux_kernel >= 6.1.9, < 6.1.30`
- `linux_kernel >= 6.2.1, < 6.3.4`
- `linux_kernel = 6.2`
- `linux_kernel = 6.4`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.3.4`