What’s Vulnerable › Vulnerabilities

CVE-2021-31401

• 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-20

Description

An issue was discovered in tcp_rcv() in nptcp.c in HCC embedded InterNiche 4.0.1. The TCP header processing code doesn't sanitize the value of the IP total length field (header length + data length). With a crafted IP packet, an integer overflow occurs whenever the value of the IP data length is calculated by subtracting the length of the header from the total length of the IP packet.

Affected products

• Hcc-Embedded Nichestack: before 4.3 — fixed in 4.3
• Siemens Sentron 3Wa Com190 Firmware: before 2.0.0 — fixed in 2.0.0
• Siemens Sentron 3Wl Com35 Firmware: before 1.2.0 — fixed in 1.2.0

How to fix

Upgrade to a fixed version: Hcc-Embedded Nichestack 4.3; Siemens Sentron 3Wa Com190 Firmware 2.0.0; Siemens Sentron 3Wl Com35 Firmware 1.2.0. 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.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.kb.cert.org/vuls/id/608209

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