Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2021-3997

CVE-2021-3997MEDIUM

n/a systemd — A flaw was found in systemd.

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  N  N  H    5.5   .0172   77.1     —

AFFECTED
  Product  Versions             Fixed
  systemd  Fixed in v251-rc1 –  —

TIMELINE
  Nov 22  Reserved by redhat
  Aug 23  Published (CNA: redhat)
  Oct 14  ENRICHED — CVE-2021-3997 (systemd). Received CVSS 5.5 and CPE data from NVD.
  Oct 14  EXPLOIT PUBLISHED — CVE-2021-3997 (systemd). Public exploit reference added.

CWE-674 · CNA: redhat · CVSS v3.1 · 6 references · NVD status: Modified

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.

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
November 22, 2021	Reserved	Reserved by redhat
August 23, 2022	Published	Published (CNA: redhat)
October 14, 2026	ENRICHED	ENRICHED — CVE-2021-3997 (systemd). Received CVSS 5.5 and CPE data from NVD.
October 14, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2021-3997 (systemd). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	systemd	—	Fixed in v251-rc1	—

Weaknesses

CWE-674

References (6)

https://access.redhat.com/security/cve/CVE-2021-3997 [Issue Tracking, Third Party Advisory]
https://bugzilla.redhat.com/show_bug.cgi?id=2024639 [Issue Tracking, Patch, Third Party Advisory]
https://cert-portal.siemens.com/productcert/html/ssa-398330.html
https://github.com/systemd/systemd/commit/5b1cf7a9be37e20133c0208005274ce4a5b5c6a1 [Patch, Third Party Advisory]
https://security.gentoo.org/glsa/202305-15
https://www.openwall.com/lists/oss-security/2022/01/10/2 [Exploit, Mailing List, Third Party Advisory]

Authoritative record: CVE-2021-3997 at cve.org

Weaknesses: CWE-674

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-3997 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.