---
id: CVE-2021-3999
title: A flaw was found in glibc
summary: >-
  A flaw was found in glibc. An off-by-one buffer overflow and underflow in
  getcwd() may lead to memory corruption when the size of the buffer is exactly
  1. A local attacker who can control the input buffer and size passed to
  getcwd() in a…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-193
  - CWE-193
vendor: gnu
product: glibc
affected:
  - glibc < 2.31
  - debian_linux = 10.0
  - debian_linux = 11.0
  - e-series_performance_analyzer
  - nfs_plug-in
  - ontap_select_deploy_administration_utility
  - h300s_firmware
  - h500s_firmware
  - h700s_firmware
  - h410s_firmware
  - h410c_firmware
patched:
  - glibc 2.31
published: '2022-08-24'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T10:17:50.007'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-3999'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2021-3999'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2024637'
    label: secalert@redhat.com
  - url: 'https://lists.debian.org/debian-lts-announce/2022/10/msg00021.html'
    label: secalert@redhat.com
  - url: 'https://security-tracker.debian.org/tracker/CVE-2021-3999'
    label: secalert@redhat.com
  - url: 'https://security.netapp.com/advisory/ntap-20221104-0001/'
    label: secalert@redhat.com
  - url: 'https://sourceware.org/bugzilla/show_bug.cgi?id=28769'
    label: secalert@redhat.com
  - url: >-
      https://sourceware.org/git/gitweb.cgi?p=glibc.git%3Bh=23e0e8f5f1fb5ed150253d986ecccdc90c2dcd5e
    label: secalert@redhat.com
  - url: 'https://www.openwall.com/lists/oss-security/2022/01/24/4'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2021-3999'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2024637'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2022/10/msg00021.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security-tracker.debian.org/tracker/CVE-2021-3999'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.netapp.com/advisory/ntap-20221104-0001/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://sourceware.org/bugzilla/show_bug.cgi?id=28769'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://sourceware.org/git/gitweb.cgi?p=glibc.git%3Bh=23e0e8f5f1fb5ed150253d986ecccdc90c2dcd5e
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.openwall.com/lists/oss-security/2022/01/24/4'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-398330.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-831302.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
epss: 0.00746
epssPercentile: 0.53596
ingestedAt: '2026-10-14T10:25:41.194Z'
---

## Overview

A flaw was found in glibc. An off-by-one buffer overflow and underflow in getcwd() may lead to memory corruption when the size of the buffer is exactly 1. A local attacker who can control the input buffer and size passed to getcwd() in a setuid program could use this flaw to potentially execute arbitrary code and escalate their privileges on the system.

## Affected

- `glibc < 2.31`
- `debian_linux = 10.0`
- `debian_linux = 11.0`
- `e-series_performance_analyzer`
- `nfs_plug-in`
- `ontap_select_deploy_administration_utility`
- `h300s_firmware`
- `h500s_firmware`
- `h700s_firmware`
- `h410s_firmware`
- `h410c_firmware`

## Remediation

Upgrade past the affected range:

- `glibc 2.31`