---
id: CVE-2021-4166
title: vim is vulnerable to Out-of-bounds Read
summary: vim is vulnerable to Out-of-bounds Read
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H'
cwe:
  - CWE-125
vendor: vim
product: vim
affected:
  - vim < 8.2.3884
  - enterprise_linux = 8.0
  - factory
  - linux_enterprise = 12.0
  - linux_enterprise = 15.0
  - debian_linux = 9.0
  - debian_linux = 10.0
  - debian_linux = 11.0
  - fedora = 34
  - fedora = 35
  - mac_os_x = 10.15.7
  - macos < 12.3
  - 'macos >= 11.0, < 11.6.6'
  - macos = 10.15.7
patched:
  - vim 8.2.3884
  - macos 11.6.6
published: '2021-12-25'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:17:42.890'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-4166'
references:
  - url: 'http://seclists.org/fulldisclosure/2022/Jul/14'
    label: security@huntr.dev
  - url: 'http://seclists.org/fulldisclosure/2022/Mar/29'
    label: security@huntr.dev
  - url: 'http://seclists.org/fulldisclosure/2022/May/35'
    label: security@huntr.dev
  - url: 'http://www.openwall.com/lists/oss-security/2022/01/15/1'
    label: security@huntr.dev
  - url: 'https://github.com/vim/vim/commit/6f98371532fcff911b462d51bc64f2ce8a6ae682'
    label: security@huntr.dev
  - url: 'https://huntr.dev/bounties/229df5dd-5507-44e9-832c-c70364bdf035'
    label: security@huntr.dev
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2EY2VFBU3YGGWI5BW4XKT3F37MYGEQUD/
    label: security@huntr.dev
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3FH2J57GDA2WMBS6J56F6QQRA6BXQQFZ/
    label: security@huntr.dev
  - url: 'https://security.gentoo.org/glsa/202208-32'
    label: security@huntr.dev
  - url: 'https://support.apple.com/kb/HT213183'
    label: security@huntr.dev
  - url: 'https://support.apple.com/kb/HT213256'
    label: security@huntr.dev
  - url: 'https://support.apple.com/kb/HT213343'
    label: security@huntr.dev
  - url: 'http://seclists.org/fulldisclosure/2022/Jul/14'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://seclists.org/fulldisclosure/2022/Mar/29'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://seclists.org/fulldisclosure/2022/May/35'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://www.openwall.com/lists/oss-security/2022/01/15/1'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/vim/vim/commit/6f98371532fcff911b462d51bc64f2ce8a6ae682'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://huntr.dev/bounties/229df5dd-5507-44e9-832c-c70364bdf035'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2EY2VFBU3YGGWI5BW4XKT3F37MYGEQUD/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3FH2J57GDA2WMBS6J56F6QQRA6BXQQFZ/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.gentoo.org/glsa/202208-32'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://support.apple.com/kb/HT213183'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://support.apple.com/kb/HT213256'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://support.apple.com/kb/HT213343'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-4166.json
  - url: 'https://access.redhat.com/security/cve/CVE-2021-4166'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2035928'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2021-4166'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2021-4166'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.01578
epssPercentile: 0.74741
ingestedAt: '2026-10-08T22:11:53.744Z'
---

## Overview

vim is vulnerable to Out-of-bounds Read

## Affected

- `vim < 8.2.3884`
- `enterprise_linux = 8.0`
- `factory`
- `linux_enterprise = 12.0`
- `linux_enterprise = 15.0`
- `debian_linux = 9.0`
- `debian_linux = 10.0`
- `debian_linux = 11.0`
- `fedora = 34`
- `fedora = 35`
- `mac_os_x = 10.15.7`
- `macos < 12.3`
- `macos >= 11.0, < 11.6.6`
- `macos = 10.15.7`

## Remediation

Upgrade past the affected range:

- `vim 8.2.3884`
- `macos 11.6.6`

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-10-08 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-4166.json)