{"cve":"CVE-2021-33820","nvd":{"published":"2021-06-18T19:15:07.537","modified":"2026-06-17T03:55:16.233","status":"Modified","description":"An issue was discovered in UniFi Protect G3 FLEX Camera Version UVC.v4.30.0.67.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-2021-33820.md","https://linuxhint.com/hping3/","https://store.ui.com/collections/unifi-protect-cameras/products/unifi-video-g3-flex-camera","https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33820.md","https://linuxhint.com/hping3/"],"products":["ui:camera_g3_flex_firmware"],"source":"nvd","synced_at":"2026-10-19T21:20:07.141963181+00:00"},"epss":{"cve":"CVE-2021-33820","score":0.01934,"percentile":0.80048,"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."]}