{"cve":"CVE-2021-33823","nvd":{"published":"2021-06-18T20:15:07.767","modified":"2026-06-17T03:55:16.457","status":"Modified","description":"An issue was discovered on MOXA Mgate MB3180 Version 2.1 Build 18113012. Attacker could send a huge amount of TCP SYN packet to make web service's resource exhausted. Then the web server is denial-of-service.","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":[],"references":["https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33823.md","https://www.moxa.com/en/products/industrial-edge-connectivity/protocol-gateways/modbus-tcp-gateways/mgate-mb3180-mb3280-mb3480-series","https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33823.md","https://www.moxa.com/en/products/industrial-edge-connectivity/protocol-gateways/modbus-tcp-gateways/mgate-mb3180-mb3280-mb3480-series"],"products":["moxa:mgate_mb3180_firmware"],"source":"nvd","synced_at":"2026-10-19T21:20:07.141963181+00:00"},"epss":{"cve":"CVE-2021-33823","score":0.01321,"percentile":0.70879,"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."]}