What is the CVSS score of CVE-2018-16556?

CVE-2018-16556 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 1.5%.

Simatic S7 400 Firmware CVE-2018-16556

HIGH

Improper Input Validation (CWE-20)

2018-12-13 productcert@siemens.com

Denial Of Service Siemens Simatic S7 400 Firmware Simatic S7 400H V6 Firmware Simatic S7 400 Pn Dp V7 Firmware Simatic S7 410 Firmware Simatic S7 400H Firmware

7.5

CVSS 3.1 · Vendor: siemens

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Vulnerability Assessment

Weakness	CWE CWE-20 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V2 - Validation and Business Logic Input validation, allowlisting
Impact	CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the high-severity affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 1.5% exploitation probability (EPSS)

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AnalysisAI

A vulnerability has been identified in SIMATIC S7-400 CPU 412-1 DP V7 (All versions), SIMATIC S7-400 CPU 412-2 DP V7 (All versions), SIMATIC S7-400 CPU 414-2 DP V7 (All versions), SIMATIC S7-400 CPU. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

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Technical ContextAI · show details

This vulnerability is classified under CWE-20. A vulnerability has been identified in SIMATIC S7-400 CPU 412-1 DP V7 (All versions), SIMATIC S7-400 CPU 412-2 DP V7 (All versions), SIMATIC S7-400 CPU 414-2 DP V7 (All versions), SIMATIC S7-400 CPU 414-3 DP V7 (All versions), SIMATIC S7-400 CPU 414-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 414F-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 416-2 DP V7 (All versions), SIMATIC S7-400 CPU 416-3 DP V7 (All versions), SIMATIC S7-400 CPU 416-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 416F-2 DP V7 (All versions), SIMATIC S7-400 CPU 416F-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 417-4 DP V7 (All versions), SIMATIC S7-400 CPU 412-2 PN V7 (All versions < V7.0.3), SIMATIC S7-400 H V4.5 and below CPU family (incl. SIPLUS variants) (All versions), SIMATIC S7-400 H V6 CPU family (incl. SIPLUS variants) (All versions < V6.0.9), SIMATIC S7-400 PN/DP V6 and below CPU family (incl. SIPLUS variants) (All versions), SIMATIC S7-410 CPU family (incl. SIPLUS variants) (All versions < V8.2.1), SIPLUS S7-400 CPU 414-3 PN/DP V7 (All versions < V7.0.3), SIPLUS S7-400 CPU 416-3 PN/DP V7 (All versions < V7.0.3), SIPLUS S7-400 CPU 416-3 V7 (All versions), SIPLUS S7-400 CPU 417-4 V7 (All versions). Specially crafted packets sent to port 102/tcp via Ethernet interface, via PROFIBUS, or via Multi Point Interfaces (MPI) could cause the affected devices to go into defect mode. Manual reboot is required to resume normal operation. Successful exploitation requires an attacker to be able to send specially crafted packets to port 102/tcp via Ethernet interface, via PROFIBUS or Multi Point Interfaces (MPI). No user interaction and no user 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. Affected products include: Siemens Simatic S7-400 Firmware, Siemens Simatic S7-400 Pn\/Dp V7 Firmware, Siemens Simatic S7-400H Firmware, Siemens Simatic S7-410 Firmware, Siemens Simatic S7-400H V6 Firmware.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (siemens) PRIMARY 7.5 HIGH

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

Primary rating from Vendor (siemens) · only source for this CVE.

CVSS VectorVendor: siemens

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

DescriptionCVE.org

A vulnerability has been identified in SIMATIC S7-400 CPU 412-1 DP V7 (All versions), SIMATIC S7-400 CPU 412-2 DP V7 (All versions), SIMATIC S7-400 CPU 414-2 DP V7 (All versions), SIMATIC S7-400 CPU 414-3 DP V7 (All versions), SIMATIC S7-400 CPU 414-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 414F-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 416-2 DP V7 (All versions), SIMATIC S7-400 CPU 416-3 DP V7 (All versions), SIMATIC S7-400 CPU 416-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 416F-2 DP V7 (All versions), SIMATIC S7-400 CPU 416F-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 417-4 DP V7 (All versions), SIMATIC S7-400 CPU 412-2 PN V7 (All versions < V7.0.3), SIMATIC S7-400 H V4.5 and below CPU family (incl. SIPLUS variants) (All versions), SIMATIC S7-400 H V6 CPU family (incl. SIPLUS variants) (All versions < V6.0.9), SIMATIC S7-400 PN/DP V6 and below CPU family (incl. SIPLUS variants) (All versions), SIMATIC S7-410 CPU family (incl. SIPLUS variants) (All versions < V8.2.1), SIPLUS S7-400 CPU 414-3 PN/DP V7 (All versions < V7.0.3), SIPLUS S7-400 CPU 416-3 PN/DP V7 (All versions < V7.0.3), SIPLUS S7-400 CPU 416-3 V7 (All versions), SIPLUS S7-400 CPU 417-4 V7 (All versions). Specially crafted packets sent to port 102/tcp via Ethernet interface, via PROFIBUS, or via Multi Point Interfaces (MPI) could cause the affected devices to go into defect mode. Manual reboot is required to resume normal operation.

Successful exploitation requires an attacker to be able to send specially crafted packets to port 102/tcp via Ethernet interface, via PROFIBUS or Multi Point Interfaces (MPI). No user interaction and no user 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.

Threat Intelligence Overview

EPSS Score

1.5%

Top 28% exploitable

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 1.5%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.