---
id: CVE-2023-52440
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ksmbd: fix slub overflow in ksmbd_decode_ntlmssp_auth_blob()

  If authblob->SessionKey.Length is bigger than session key
  size(CIFS_KEY_SIZE), slub overflow can happen in…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ksmbd: fix slub overflow in ksmbd_decode_ntlmssp_auth_blob()

  If authblob->SessionKey.Length is bigger than session key
  size(CIFS_KEY_SIZE), slub overflow can happen in…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-119
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.17.0, < 6.1.52'
  - 'linux_kernel >= 6.2.0, < 6.4.15'
  - 'linux_kernel >= 6.5.0, < 6.5.2'
patched:
  - linux_kernel 6.5.2
published: '2024-02-21'
updated: '2026-08-04'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2023-52440'
references:
  - url: 'https://git.kernel.org/stable/c/30fd6521b2fbd9b767e438e31945e5ea3e3a2fba'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4b081ce0d830b684fdf967abc3696d1261387254'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7f1d6cb0eb6af3a8088dc24b7ddee9a9711538c4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bd554ed4fdc3d38404a1c43d428432577573e809'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ecd7e1c562cb08e41957fcd4b0e404de5ab38e20'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/30fd6521b2fbd9b767e438e31945e5ea3e3a2fba'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/4b081ce0d830b684fdf967abc3696d1261387254'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/7f1d6cb0eb6af3a8088dc24b7ddee9a9711538c4'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/bd554ed4fdc3d38404a1c43d428432577573e809'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/ecd7e1c562cb08e41957fcd4b0e404de5ab38e20'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - exploit-available
epss: 0.21909
epssPercentile: 0.97594
ingestedAt: '2026-08-04T10:39:37.463Z'
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/BitsByWill/ksmbd-n-day'
  checkedAt: '2026-09-21T15:26:12.436Z'
exploitAvailable: true
---

## Overview

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

ksmbd: fix slub overflow in ksmbd_decode_ntlmssp_auth_blob()

If authblob->SessionKey.Length is bigger than session key
size(CIFS_KEY_SIZE), slub overflow can happen in key exchange codes.
cifs_arc4_crypt copy to session key array from SessionKey from client.

## Affected

- `linux_kernel >= 5.17.0, < 6.1.52`
- `linux_kernel >= 6.2.0, < 6.4.15`
- `linux_kernel >= 6.5.0, < 6.5.2`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.5.2`