{"cve":"CVE-2021-31401","nvd":{"published":"2021-08-19T12:15:08.893","modified":"2026-06-17T03:51:42.607","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-20"],"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/"],"products":["hcc-embedded:nichestack","siemens:sentron_3wa_com190_firmware","siemens:sentron_3wl_com35_firmware"],"source":"nvd","synced_at":"2026-10-19T21:21:57.125947417+00:00"},"epss":{"cve":"CVE-2021-31401","score":0.02252,"percentile":0.82915,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}