CVE-2021-31401

Name: CVE-2021-31401
Creator: NVD / NIST
Published: 2021-08-19T12:15:08.893+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.25%

Last modified Jun 17, 2026

CVE-2021-31401 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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). EPSS estimates a 2.25% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

2.25%

80.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-20

Affected Software

Vendor	Product	Versions
Hcc-Embedded	Nichestack	< 4.3
Siemens	Sentron 3wl Com35 Firmware	< 1.2.0
Siemens	Sentron 3wa Com190 Firmware	< 2.0.0

References

https://cert-portal.siemens.com/productcert/pdf/ssa-789208.pdfMitigation, Third Party Advisory
https://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/Mitigation, Third Party Advisory
https://www.kb.cert.org/vuls/id/608209Third Party Advisory, US Government Resource
https://cert-portal.siemens.com/productcert/pdf/ssa-789208.pdfMitigation, Third Party Advisory
https://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/Mitigation, Third Party Advisory
https://www.kb.cert.org/vuls/id/608209Third Party Advisory, US Government Resource

Timeline

Published: Aug 19, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-31401?

How severe is CVE-2021-31401?

CVE-2021-31401 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.25% probability of exploitation in the next 30 days.

How do I fix CVE-2021-31401?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-31401?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST