Skip to content
Noroxi
NVD / CVE Program· CNA redhat

CVE-2021-3997: A flaw was found in systemd.

MediumCVSS 5.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 23/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1.7% (FIRST EPSS); higher than 77.9% of all records.
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: systemd (Debian:12) 250.2-1; htmldoc (openSUSE:Leap 15.3) 1.9.12-bp153.2.6.1; systemd (openSUSE:Leap 15.3) 246.16-7.33.1, 246.16-150300.7.39.1.

Low priority for now. Upgrade to systemd (Debian:12) 250.2-1; htmldoc (openSUSE:Leap 15.3) 1.9.12-bp153.2.6.1; systemd (openSUSE:Leap 15.3) 246.16-7.33.1, 246.16-150300.7.39.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Aug 23, 2022
Updated
Nov 2, 2026
EPSS
1.7% · 77th percentile

Report tools

JSON

Action score

23

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 1.7%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-3997

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for systemd project records
Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
systemd projectsystemd
fedoraprojectfedora
redhatenterprise linux

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • n/a systemd

    • Fixed in v251-rc1affected
Affected versions · NVD (6)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • fedoraproject fedora34
  • fedoraproject fedora35
  • redhat enterprise linux7.0
  • redhat enterprise linux8.0
  • redhat enterprise linux9.0
  • systemd project systemd240 and later · before 250.2

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12systemdbefore 250.2-1250.2-1
openSUSE:Leap 15.3htmldocbefore 1.9.12-bp153.2.6.11.9.12-bp153.2.6.1
openSUSE:Leap 15.3systemdbefore 246.16-7.33.1246.16-7.33.1
openSUSE:Leap 15.3systemdbefore 246.16-150300.7.39.1246.16-150300.7.39.1
openSUSE:Tumbleweedsystemdbefore 249.7-3.1249.7-3.1
SUSE:Linux Enterprise Module for Basesystem 15 SP3systemdbefore 246.16-150300.7.39.1246.16-150300.7.39.1
SUSE:Linux Enterprise Module for Basesystem 15 SP3systemdbefore 246.16-7.33.1246.16-7.33.1
SUSE:Package Hub 15 SP3htmldocbefore 1.9.12-bp153.2.6.11.9.12-bp153.2.6.1

Same product

systemd project: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-9445In systemd through 233, certain sizes passed to dns_packet_new in systemd-resolved can cause it to allocate a buffer that's too small.
    48Plan
  • CVE-2018-21029systemd 239 through 245 accepts any certificate signed by a trusted certificate authority for DNS Over TLS.
    40Plan
  • CVE-2015-7510Stack-based buffer overflow in the getpwnam and getgrnam functions of the NSS module nss-mymachines in systemd.
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2020-13529May 10, 2021 · An exploitable denial-of-service vulnerability exists in Systemd 245.
    24Monitor
  • ← EarlierCVE-2021-33910Jul 20, 2021 · basic/unit-name.c in systemd prior to 246.15, 247.8, 248.5, and 249.1 has a Memory Allocation with an Excessive Size Value (involving…
    25Monitor
  • Later →CVE-2022-2526Sep 9, 2022 · A use-after-free vulnerability was found in systemd.
    39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:systemd250.2-1 · Debian:12Package registry (OSV)
opensuse:htmldoc1.9.12-bp153.2.6.1 · openSUSE:Leap 15.3Package registry (OSV)
opensuse:systemd246.16-7.33.1 · openSUSE:Leap 15.3Package registry (OSV)
suse:htmldoc1.9.12-bp153.2.6.1 · SUSE:Package Hub 15 SP3Package registry (OSV)
suse:systemd246.16-7.33.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP3Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Not on record for this CVE: EPSS history · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-674 · Uncontrolled Recursion

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records