---
id: CVE-2021-45402
title: >-
  The check_alu_op() function in kernel/bpf/verifier.c in the Linux kernel
  through v5.16-rc5 did not properly update bounds while handling the mov32
  instruction, which allows local users to obtain potentially sensitive address
  information,…
summary: >-
  The check_alu_op() function in kernel/bpf/verifier.c in the Linux kernel
  through v5.16-rc5 did not properly update bounds while handling the mov32
  instruction, which allows local users to obtain potentially sensitive address
  information,…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-668
vendor: linux
product: linux_kernel
affected:
  - linux_kernel < 5.16
  - linux_kernel = 5.16
patched:
  - linux_kernel 5.16
published: '2022-02-11'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:17:42.407'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-45402'
references:
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=3cf2b61eb06765e27fec6799292d9fb46d0b7e60
    label: cve@mitre.org
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=b1a7288dedc6caf9023f2676b4f5ed34cf0d4029
    label: cve@mitre.org
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=e572ff80f05c33cd0cb4860f864f5c9c044280b6
    label: cve@mitre.org
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=3cf2b61eb06765e27fec6799292d9fb46d0b7e60
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=b1a7288dedc6caf9023f2676b4f5ed34cf0d4029
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=e572ff80f05c33cd0cb4860f864f5c9c044280b6
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00416
epssPercentile: 0.33909
ingestedAt: '2026-10-08T22:11:53.747Z'
---

## Overview

The check_alu_op() function in kernel/bpf/verifier.c in the Linux kernel through v5.16-rc5 did not properly update bounds while handling the mov32 instruction, which allows local users to obtain potentially sensitive address information, aka a "pointer leak."

## Affected

- `linux_kernel < 5.16`
- `linux_kernel = 5.16`

## Remediation

Upgrade past the affected range:

- `linux_kernel 5.16`