What’s Vulnerable › Vulnerabilities

CVE-2021-3997

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-08-23 · updated 2026-10-14
• Weakness: CWE-674

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.

Affected products

• Fedoraproject Fedora: 34, 35
• Red Hat Enterprise Linux: 7.0, 8.0, 9.0
• systemd: from 240 before 250.2 — fixed in 250.2

How to fix

Upgrade to a fixed version: systemd 250.2. Check the vendor advisory for mitigations.

References

• https://access.redhat.com/security/cve/CVE-2021-3997
• https://bugzilla.redhat.com/show_bug.cgi?id=2024639
• https://github.com/systemd/systemd/commit/5b1cf7a9be37e20133c0208005274ce4a5b5c6a1
• https://security.gentoo.org/glsa/202305-15
• https://www.openwall.com/lists/oss-security/2022/01/10/2
• https://access.redhat.com/security/cve/CVE-2021-3997
• https://bugzilla.redhat.com/show_bug.cgi?id=2024639
• https://github.com/systemd/systemd/commit/5b1cf7a9be37e20133c0208005274ce4a5b5c6a1
• https://security.gentoo.org/glsa/202305-15
• https://www.openwall.com/lists/oss-security/2022/01/10/2
• https://cert-portal.siemens.com/productcert/html/ssa-398330.html

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