{"cve":"CVE-2021-33318","nvd":{"published":"2022-05-16T16:15:07.810","modified":"2026-06-17T03:54:26.300","status":"Modified","description":"An Input Validation Vulnerability exists in Joel Christner .NET C# packages WatsonWebserver, IpMatcher 1.0.4.1 and below (IpMatcher) and 4.1.3 and below (WatsonWebserver) due to insufficient validation of input IP addresses and netmasks against the internal Matcher list of IP addresses and subnets.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-704"],"references":["https://github.com/jchristn/IpMatcher","https://github.com/jchristn/IpMatcher/commit/81d77c2f33aa912dbd032b34b9e184fc6e041d89","https://github.com/jchristn/WatsonWebserver","https://github.com/kaoudis/advisories/blob/main/0-2021.md","https://github.com/jchristn/IpMatcher"],"products":["ipmatcher_project:ipmatcher","watsonwebserver_project:watsonwebserver"],"source":"nvd","synced_at":"2026-10-19T21:31:59.322382750+00:00"},"epss":{"cve":"CVE-2021-33318","score":0.02052,"percentile":0.81259,"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."]}