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Vulnerability record · CVE-2021-22909 · published 27 May 2021

CVE-2021-22909: Ui edgemax edgerouter firmware improper certificate validation vulnerability

Ui · Edgemax Edgerouter Firmware

A vulnerability found in EdgeMAX EdgeRouter V2.0.9 and earlier could allow a malicious actor to execute a man-in-the-middle (MitM) attack during a firmware update. This vulnerability is fixed in EdgeMAX EdgeRouter V2.0.9-hotfix.1 and later.

7.5 CVSS 3.1 High EPSS 1.3% · top 30.9% CWE-300 · CWE-300CWE-295 · Improper certificate validation
7.5CVSS 3.1 base score, v2 7.6
1.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

A vulnerability found in EdgeMAX EdgeRouter V2.0.9 and earlier could allow a malicious actor to execute a man-in-the-middle (MitM) attack during a firmware update. This vulnerability is fixed in EdgeMAX EdgeRouter V2.0.9-hotfix.1 and later.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://community.ui.com/releases/Security-Advisory-Bulletin-018-018/cfa1566b-4bf8-427b-8cc7-8cffba3a93a4 Vendor Advisory
https://community.ui.com/releases/Security-Advisory-Bulletin-018-018/cfa1566b-4bf8-427b-8cc7-8cffba3a93a4 Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.8CVE-2022-43553Ui edgemax edgerouter firmware execution with unnecessary privileges vulnerabilityA remote code execution vulnerability in EdgeRouters (Version 2.0.9-hotfix.4 and earlier) allows a malicious actor with an operator account to run ar…EPSS 1.1%7.5CVE-2023-31998Ui edgemax edgerouter firmware out-of-bounds write vulnerabilityA heap overflow vulnerability found in EdgeRouters and Aircubes allows a malicious actor to interrupt UPnP service to said devices.EPSS 0.80%7.3CVE-2023-2373Ui edgemax edgerouter firmware injection vulnerabilityA vulnerability was identified in Ubiquiti EdgeRouter X up to 2.0.9-hotfix.6. This vulnerability affects unknown code of the component Web Management…EPSS 7.6%

Source: NIST National Vulnerability Database (record CVE-2021-22909), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.