{"cve":"CVE-2020-35684","nvd":{"published":"2021-08-19T12:15:08.020","modified":"2026-06-17T03:14:07.667","status":"Modified","description":"An issue was discovered in HCC Nichestack 3.0. The code that parses TCP packets relies on an unchecked value of the IP payload size (extracted from the IP header) to compute the length of the TCP payload within the TCP checksum computation function. When the IP payload size is set to be smaller than the size of the IP header, the TCP checksum computation function may read out of bounds (a low-impact write-out-of-bounds is also possible).","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.hcc-embedded.com","https://www.kb.cert.org/vuls/id/608209","https://cert-portal.siemens.com/productcert/pdf/ssa-789208.pdf"],"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-2020-35684","score":0.02287,"percentile":0.83184,"date":"2026-10-31"},"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."]}