---
id: CVE-2021-33643
title: >-
  An attacker who submits a crafted tar file with size in header struct being 0
  may be able to trigger an calling of malloc(0) for a variable gnu_longlink,
  causing an out-of-bounds read.
summary: >-
  An attacker who submits a crafted tar file with size in header struct being 0
  may be able to trigger an calling of malloc(0) for a variable gnu_longlink,
  causing an out-of-bounds read.
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H'
cwe:
  - CWE-125
  - CWE-125
vendor: feep
product: libtar
affected:
  - libtar < 1.2.21
  - openeuler = 20.03
  - openeuler = 22.03
  - fedora = 35
  - fedora = 36
  - fedora = 37
patched:
  - libtar 1.2.21
published: '2022-08-10'
updated: '2026-06-23'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-33643'
references:
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4S4PJRCJLEAWN2EKXGLSOBTL7O57V7NC/
    label: securities@openeuler.org
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5YSHZY753R7XW6CIKJVAWI373WW3YRRJ/
    label: securities@openeuler.org
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7Q26QDNOJDOFYWMJWEIK5XR62M2FF6IJ/
    label: securities@openeuler.org
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7WX5YE66CT7Y5C2HTHXSFDKQWYWYWJ2T/
    label: securities@openeuler.org
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OD4HEBSTI22FNYKOKK7W3X6ZQE6FV3XC/
    label: securities@openeuler.org
  - url: >-
      https://www.openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2022-1807
    label: securities@openeuler.org
  - url: 'https://lists.debian.org/debian-lts-announce/2025/01/msg00026.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4S4PJRCJLEAWN2EKXGLSOBTL7O57V7NC/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5YSHZY753R7XW6CIKJVAWI373WW3YRRJ/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7Q26QDNOJDOFYWMJWEIK5XR62M2FF6IJ/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7WX5YE66CT7Y5C2HTHXSFDKQWYWYWJ2T/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OD4HEBSTI22FNYKOKK7W3X6ZQE6FV3XC/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://www.openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2022-1807
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01661
epssPercentile: 0.75639
ingestedAt: '2026-06-29T13:24:33.497Z'
---

## Overview

An attacker who submits a crafted tar file with size in header struct being 0 may be able to trigger an calling of malloc(0) for a variable gnu_longlink, causing an out-of-bounds read.

## Affected

- `libtar < 1.2.21`
- `openeuler = 20.03`
- `openeuler = 22.03`
- `fedora = 35`
- `fedora = 36`
- `fedora = 37`

## Remediation

Upgrade past the affected range:

- `libtar 1.2.21`