An issue was discovered in UniFi Protect G3 FLEX Camera Version UVC.v4.30.0.67.

published 2021-06-18 5y ago modified 2026-06-17 4mo ago also EUVD-2021-20493

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.9%; EPSS 1.9% chance of exploitation in 30 days, percentile 80%
public exploits: 0; none known

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.

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Exploit prediction

1.93% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

github.com https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33818.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

CWE-400 Uncontrolled Resource Consumption

References

github.com /Jian-Xian/CVE-POC/blob/master/CVE-2021-33818.md
exploit, third-party-advisory
store.ui.com /collections/unifi-protect-cameras/products/unifi-video-g3-flex-camera
product, vendor-advisory
github.com /shekyan/slowhttptest
third-party-advisory

Sources

CVE List CVE-2021-33818
NVD CVE-2021-33818

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.