CVE Tools
Track your stack

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.

No known exploitation. EPSS puts it in the 77th percentile. Fixed in 250.2.

CVSS 3.15.5MediumEPSS percentile77th1.7% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix250.2Upgrade to this build

Published Updated Sources: CVE.org, NVD, BDU, CSAF

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • N/a SystemdAffected: Fixed in v251-rc1Upgrade to: not statedStated by: CVE record
  • Systemd Project SystemdAffected: ≥ 240, < 250.2Upgrade to: 250.2Stated by: NVD
  • ООО «Ред Софт» РЕД ОСAffected: 7.3Upgrade to: not statedStated by: BDU
  • АО «НППКТ» ОСОН ОСнова ОnyxAffected: до 2.7Upgrade to: not statedStated by: BDU
  • Сообщество свободного программного обеспечения SystemdAffected: от 240 до 250.2Upgrade to: not statedStated by: BDU

Versions as the sources state them. Full version matrix after sign-in

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the firmware version >= V3.1.0 and < V3.1.5 for the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant). These GNU/Linux vulnerabilities have been externally identified. Siemens has released new versions for the affected products and recommends to update to the latest versions. Note: This SSA advises vulnerabilities for firmware version V3.1 only; for versions < V3.1 refer to Siemens Security Bulletin SSB-439005 ( https://cert-portal.siemens.com/productcert/html/ssb-439005.html).

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS77th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

1.7% chance of exploitation activity in the next 30 days, which ranks it in the 77th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

8 events over 1513 days, from the signal feeds we watch.

  1. Patch availablerecord updated
  2. OpenVAS check added
  3. Patch availablerecord updated
  4. Publishedweakness classified, att&ck mapped

Affected products

And 1 more affected product. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

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

Scored 5.5 by NVD.

How it is reached

  • Attack Vector LocalRequires local access to the vulnerable system (e.g. local login, malicious file)
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required LowRequires basic user-level privileges
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity NoneNo integrity impact
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 17 more references. See all after sign-in

Watch the software you run.

My Stack ranks new CVEs for your products by real-world exploitation, so the next serious one reaches you without reading every advisory.

We'll flag the next CVE, public exploit or patch for РЕД ОС, not every advisory.