---
id: CVE-2021-3997
title: A flaw was found in systemd
summary: >-
  A flaw was found in systemd. An uncontrolled recursion in systemd-tmpfiles may
  lead to a denial of service at boot time when too many nested directories are
  created in /tmp.
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-674
  - CWE-674
vendor: systemd_project
product: systemd
affected:
  - 'systemd >= 240, < 250.2'
  - fedora = 34
  - fedora = 35
  - enterprise_linux = 7.0
  - enterprise_linux = 8.0
  - enterprise_linux = 9.0
patched:
  - systemd 250.2
published: '2022-08-23'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T10:17:49.307'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-3997'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2021-3997'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2024639'
    label: secalert@redhat.com
  - url: >-
      https://github.com/systemd/systemd/commit/5b1cf7a9be37e20133c0208005274ce4a5b5c6a1
    label: secalert@redhat.com
  - url: 'https://security.gentoo.org/glsa/202305-15'
    label: secalert@redhat.com
  - url: 'https://www.openwall.com/lists/oss-security/2022/01/10/2'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2021-3997'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2024639'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://github.com/systemd/systemd/commit/5b1cf7a9be37e20133c0208005274ce4a5b5c6a1
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.gentoo.org/glsa/202305-15'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.openwall.com/lists/oss-security/2022/01/10/2'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-398330.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
epss: 0.01694
epssPercentile: 0.7653
ingestedAt: '2026-10-14T10:25:41.193Z'
---

## Overview

A flaw was found in systemd. An uncontrolled recursion in systemd-tmpfiles may lead to a denial of service at boot time when too many nested directories are created in /tmp.

## Affected

- `systemd >= 240, < 250.2`
- `fedora = 34`
- `fedora = 35`
- `enterprise_linux = 7.0`
- `enterprise_linux = 8.0`
- `enterprise_linux = 9.0`

## Remediation

Upgrade past the affected range:

- `systemd 250.2`