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Vulnerabilities

Vulnerability · CVE-2021-3997

A flaw was found in systemd.

Published Aug 23, 2022 · catalog updated Oct 14, 2026 · systemd project

Check if you run it

No confirmed exploitation is on record for CVE-2021-3997. EPSS is 1.70%. Act only if a listed version of systemd project is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.70%
Remediation
Advisory link
Affected products
cpe fedoraproject/fedora · cpe redhat/enterprise linux · cpe systemd project/systemd

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe fedoraproject/fedora34
  • cpe fedoraproject/fedora35
  • cpe redhat/enterprise linux7.0
  • cpe redhat/enterprise linux8.0
  • cpe redhat/enterprise linux9.0
  • cpe systemd project/systemdversion unspecified

How to fix CVE-2021-3997

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2021-3997. EPSS is 1.70%. Act only if a listed version of systemd project is installed.

Which versions are affected?

Compare what you have installed with redhat/enterprise linux 7.0; redhat/enterprise linux 8.0; redhat/enterprise linux 9.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-674. EPSS 1.70%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 23, 2022 · NIST NVD

    Detected

    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.

  2. Oct 14, 2026 · NIST NVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2021-3997

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-3997

    30-day exploitation probability 1.7%

    first.org
  • NIST NVDVulnerability recordCVE-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.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 16, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.