CVE-2021-33820

Name: CVE-2021-33820
Creator: NVD / NIST
Published: 2021-06-18T19:15:07.537+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.93%

Last modified Jun 17, 2026

CVE-2021-33820 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 1.93% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

1.93%

77.5th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Ui	Camera G3 Flex Firmware	uvc.v4.30.0.67

References

https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33820.mdExploit, Third Party Advisory
https://linuxhint.com/hping3/Third Party Advisory
https://store.ui.com/collections/unifi-protect-cameras/products/unifi-video-g3-flex-cameraProduct, Vendor Advisory
https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33820.mdExploit, Third Party Advisory
https://linuxhint.com/hping3/Third Party Advisory
https://store.ui.com/collections/unifi-protect-cameras/products/unifi-video-g3-flex-cameraProduct, Vendor Advisory

Timeline

Published: Jun 18, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-33820?

How severe is CVE-2021-33820?

CVE-2021-33820 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.93% probability of exploitation in the next 30 days.

How do I fix CVE-2021-33820?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-33820?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST