CVE-2021-33818 json
An issue was discovered in UniFi Protect G3 FLEX Camera Version UVC.v4.30.0.67.
published 2021-06-18 5 y ago modified 2026-06-17 4 mo 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
Summary
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.
Exploit prediction
1.93% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).
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 Vulns 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.