CVE-2021-3997

Name: CVE-2021-3997
Creator: NVD / NIST
Published: 2022-08-23T20:15:08.67+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 1.56%

Last modified Jun 17, 2026

CVE-2021-3997 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. 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.. EPSS estimates a 1.56% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

1.56%

72.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Systemd Project	Systemd	>= 240, < 250.2
Fedoraproject	Fedora	34
Fedoraproject	Fedora	35
Redhat	Enterprise Linux	7.0
Redhat	Enterprise Linux	8.0
Redhat	Enterprise Linux	9.0

References

https://access.redhat.com/security/cve/CVE-2021-3997Issue Tracking, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2024639Issue Tracking, Patch, Third Party Advisory
https://github.com/systemd/systemd/commit/5b1cf7a9be37e20133c0208005274ce4a5b5c6a1Patch, Third Party Advisory
https://security.gentoo.org/glsa/202305-15
https://www.openwall.com/lists/oss-security/2022/01/10/2Exploit, Mailing List, Third Party Advisory
https://access.redhat.com/security/cve/CVE-2021-3997Issue Tracking, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2024639Issue Tracking, Patch, Third Party Advisory
https://github.com/systemd/systemd/commit/5b1cf7a9be37e20133c0208005274ce4a5b5c6a1Patch, Third Party Advisory
https://security.gentoo.org/glsa/202305-15
https://www.openwall.com/lists/oss-security/2022/01/10/2Exploit, Mailing List, Third Party Advisory

Timeline

Published: Aug 23, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3997?

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.

How severe is CVE-2021-3997?

CVE-2021-3997 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 1.56% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3997?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3997?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST