What’s Vulnerable › Vulnerabilities

CVE-2020-35683

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-08-19 · updated 2026-06-17
• Weakness: CWE-125

Description

An issue was discovered in HCC Nichestack 3.0. The code that parses ICMP packets relies on an unchecked value of the IP payload size (extracted from the IP header) to compute the ICMP checksum. When the IP payload size is set to be smaller than the size of the IP header, the ICMP checksum computation function may read out of bounds, causing a Denial-of-Service.

Affected products

• Hcc-Embedded Nichestack: 3.0
• Siemens 7Km9300-0Ae02-0Aa0 Firmware: before 3.0.4 — fixed in 3.0.4

How to fix

Upgrade to a fixed version: Siemens 7Km9300-0Ae02-0Aa0 Firmware 3.0.4. Check the vendor advisory for mitigations.

References

• https://cert-portal.siemens.com/productcert/pdf/ssa-789208.pdf
• https://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/
• https://www.hcc-embedded.com
• https://www.kb.cert.org/vuls/id/608209
• https://cert-portal.siemens.com/productcert/pdf/ssa-789208.pdf
• https://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/
• https://www.hcc-embedded.com
• https://www.kb.cert.org/vuls/id/608209

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