What’s Vulnerable › Vulnerabilities

CVE-2018-4850

• Severity: high (CVSS 7.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-05-16 · updated 2026-06-17
• Weakness: CWE-20

Description

A vulnerability has been identified in SIMATIC S7-400 (incl. F) CPU hardware version 4.0 and below (All versions), SIMATIC S7-400 (incl. F) CPU hardware version 5.0 (All firmware versions < V5.2), SIMATIC S7-400H CPU hardware version 4.5 and below (All versions). 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.

Affected products

• Siemens Simatic S7-400 Firmware: through 4.0; before 5.2 — fixed in 5.2
• Siemens Simatic S7-400H Firmware: through 4.5

How to fix

Upgrade to a fixed version: Siemens Simatic S7-400 Firmware 5.2. Check the vendor advisory for mitigations.

References

• http://www.securityfocus.com/bid/104217
• https://cert-portal.siemens.com/productcert/pdf/ssa-914382.pdf
• https://www.siemens.com/global/en/home/products/services/cert.html#SecurityPublications
• http://www.securityfocus.com/bid/104217
• https://cert-portal.siemens.com/productcert/pdf/ssa-914382.pdf
• https://www.siemens.com/global/en/home/products/services/cert.html#SecurityPublications

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