---
id: CVE-2023-3640
title: >-
  A possible unauthorized memory access flaw was found in the Linux kernel's
  cpu_entry_area mapping of X86 CPU data to memory, where a user may guess the
  location of exception stacks or other important data
summary: >-
  A possible unauthorized memory access flaw was found in the Linux kernel's
  cpu_entry_area mapping of X86 CPU data to memory, where a user may guess the
  location of exception stacks or other important data. Based on the previous
  CVE-2023-…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-385
  - CWE-203
vendor: linux
product: linux_kernel
affected:
  - linux_kernel
  - enterprise_linux = 8.0
  - enterprise_linux = 9.0
published: '2023-07-24'
updated: '2026-06-26'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2023-3640'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2023:6583'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2023-3640'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2217523'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2023-3640'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2217523'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - exploit-available
epss: 0.00761
epssPercentile: 0.53859
ingestedAt: '2026-06-26T16:43:13.373Z'
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/pray77/CVE-2023-3640'
  checkedAt: '2026-09-24T07:52:49.971Z'
exploitAvailable: true
---

## Overview

A possible unauthorized memory access flaw was found in the Linux kernel's cpu_entry_area mapping of X86 CPU data to memory, where a user may guess the location of exception stacks or other important data. Based on the previous CVE-2023-0597, the 'Randomize per-cpu entry area' feature was implemented in /arch/x86/mm/cpu_entry_area.c, which works through the init_cea_offsets() function when KASLR is enabled. However, despite this feature, there is still a risk of per-cpu entry area leaks. This issue could allow a local user to gain access to some important data with memory in an expected location and potentially escalate their privileges on the system.

## Affected

- `linux_kernel`
- `enterprise_linux = 8.0`
- `enterprise_linux = 9.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.