{"id":"CVE-2021-33818","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-33818","generatedAt":"2026-10-27T22:27:25.787Z","title":"Attackers can use slowhttptest tool to send incomplete HTTP request, which could make server keep waiting for the packet to finish the connection, until its resource exhausted.","description":"An issue was discovered in UniFi Protect G3 FLEX Camera Version UVC.v4.30.0.67. Attackers can use slowhttptest tool to send incomplete HTTP request, which could make server keep waiting for the packet to finish the connection, until its resource exhausted. Then the web server is denial-of-service.","published":"2021-06-18T19:15:07.000Z","lastModified":"2026-06-17T03:55:16.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-400"],"affected":["ui/camera g3 flex firmware"],"epss":{"score":0.01934,"percentile":0.79907,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (1.93%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33818.md","tags":["Exploit","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/shekyan/slowhttptest","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://store.ui.com/collections/unifi-protect-cameras/products/unifi-video-g3-flex-camera","tags":["Product","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33818.md","tags":["Exploit","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/shekyan/slowhttptest","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://store.ui.com/collections/unifi-protect-cameras/products/unifi-video-g3-flex-camera","tags":["Product","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-33818","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}