CVE-2018-16561

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2022-05-13. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

A vulnerability has been identified in SIMATIC S7-300 CPUs (All versions < V3.X.16). The affected CPUs improperly validate S7 communication packets which could cause a Denial-of-Service condition of the CPU. The CPU will remain in DEFECT mode until manual restart. Successful exploitation requires an attacker to be able to send a specially crafted S7 communication packet to a communication interface of the CPU. This includes Ethernet, PROFIBUS, and Multi Point Interfaces (MPI). No user interaction or privileges are required to exploit the security vulnerability. The vulnerability could allow causing a Denial-of-Service condition of the core functionality of the CPU, compromising the availability of the system. At the time of advisory publication no public exploitation of this security vulnerability was known. Siemens confirms the security vulnerability and provides mitigations to resolve the security issue.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
70%
KEV
Not listed

Published

April 17, 2019

Last Modified

June 2, 2026

References (2)

Vendor Advisories for CVE-2018-16561(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 28× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 118 total refreshes for this CVE.

  1. 2026-08-20 22:51 UTCEPSS rescore
  2. 2026-08-19 17:00 UTCEPSS rescore
  3. 2026-08-18 13:43 UTCEPSS rescore
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  1. 2026-07-23 14:15 UTCEPSS rescore
  2. 2026-07-23 01:34 UTCEG score recompute
  3. 2026-07-22 22:14 UTCEG score recompute
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  20. 2026-07-08 15:11 UTCEPSS rescore
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  23. 2026-07-06 16:24 UTCEPSS rescore
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  28. 2026-07-02 16:54 UTCEPSS rescore
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  42. 2026-06-23 21:30 UTCEPSS rescore
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  46. 2026-06-21 01:57 UTCEPSS rescore
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  48. 2026-06-19 19:23 UTCEPSS rescore
  49. 2026-06-18 17:50 UTCEPSS rescore
  50. 2026-06-18 17:50 UTCEPSS rescore
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  55. 2026-06-15 17:45 UTCEPSS rescore
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  58. 2026-06-13 22:58 UTCEPSS rescore
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  60. 2026-06-12 23:09 UTCEPSS rescore
  61. 2026-06-11 13:57 UTCEPSS rescore
  62. 2026-06-10 22:16 UTCEPSS rescore
  63. 2026-06-10 13:19 UTCEPSS rescore
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  74. 2026-06-04 13:10 UTCEPSS rescore
  75. 2026-06-04 13:10 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2018-16561?
CVE-2018-16561 is a high vulnerability published on April 17, 2019. A vulnerability has been identified in SIMATIC S7-300 CPUs (All versions < V3.X.16). The affected CPUs improperly validate S7 communication packets which could cause a Denial-of-Service condition of the CPU. The CPU will remain in DEFECT mode until manual restart. Successful exploitation requires…
When was CVE-2018-16561 disclosed?
CVE-2018-16561 was first published in the National Vulnerability Database on April 17, 2019, with the most recent update on June 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-16561 actively exploited?
CVE-2018-16561 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 30.3% of all scored CVEs.
What is the CVSS score of CVE-2018-16561?
CVE-2018-16561 has a CVSS v3.1 base score of 7.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2018-16561?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-16561, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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