---
id: CVE-2023-1206
title: >-
  A hash collision flaw was found in the IPv6 connection lookup table in the
  Linux kernel’s IPv6 functionality when a user makes a new kind of SYN flood
  attack
summary: >-
  A hash collision flaw was found in the IPv6 connection lookup table in the
  Linux kernel’s IPv6 functionality when a user makes a new kind of SYN flood
  attack. A user located in the local network or with a high bandwidth
  connection can in…
severity: medium
cvss: 5.7
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
  - CWE-400
vendor: linux
product: linux_kernel
affected:
  - linux_kernel < 6.5
  - enterprise_linux = 8.0
  - enterprise_linux = 9.0
  - fedora = 38
patched:
  - linux_kernel 6.5
published: '2023-06-30'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T21:17:14.790'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2023-1206'
references:
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2175903'
    label: secalert@redhat.com
  - url: 'https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html'
    label: secalert@redhat.com
  - url: 'https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html'
    label: secalert@redhat.com
  - url: 'https://security.netapp.com/advisory/ntap-20230929-0006/'
    label: secalert@redhat.com
  - url: 'https://www.debian.org/security/2023/dsa-5480'
    label: secalert@redhat.com
  - url: 'https://www.debian.org/security/2023/dsa-5492'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2175903'
    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-20230929-0006/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.debian.org/security/2023/dsa-5480'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.debian.org/security/2023/dsa-5492'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-398330.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-769027.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-794697.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-806742.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - exploit-available
epss: 0.00549
epssPercentile: 0.44601
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/SpiralBL0CK/CVE-2023-1206-CVE-2025-40040-CVE-2024-49882'
  checkedAt: '2026-10-14T21:57:39.234Z'
exploitAvailable: true
ingestedAt: '2026-10-14T21:57:04.735Z'
---

## Overview

A hash collision flaw was found in the IPv6 connection lookup table in the Linux kernel’s IPv6 functionality when a user makes a new kind of SYN flood attack. A user located in the local network or with a high bandwidth connection can increase the CPU usage of the server that accepts IPV6 connections up to 95%.

## Affected

- `linux_kernel < 6.5`
- `enterprise_linux = 8.0`
- `enterprise_linux = 9.0`
- `fedora = 38`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.5`