CVE-2021-44273

Name: CVE-2021-44273
Creator: NVD / NIST
Published: 2021-12-23T12:15:07.387+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.4/10EPSS 0.96%

Last modified Jun 17, 2026

CVE-2021-44273 is a high-severity vulnerability rated 7.4/10 on the CVSS scale. e2guardian v5.4.x <= v5.4.3r is affected by missing SSL certificate validation in the SSL MITM engine. In standalone mode (i.e., acting as a proxy or a transparent proxy), with SSL MITM enabled, e2guardian, if built with OpenSSL v1.1.x, did not validate hostnames in certificates of the web servers that it connected to, and thus was itself vulnerable to MITM attacks.. EPSS estimates a 0.96% chance of exploitation in the next 30 days.

Description

e2guardian v5.4.x <= v5.4.3r is affected by missing SSL certificate validation in the SSL MITM engine. In standalone mode (i.e., acting as a proxy or a transparent proxy), with SSL MITM enabled, e2guardian, if built with OpenSSL v1.1.x, did not validate hostnames in certificates of the web servers that it connected to, and thus was itself vulnerable to MITM attacks.

Metrics

CVSS 3.1

7.4/10

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

EPSS Probability

0.96%

57.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-295

Affected Software

Vendor	Product	Versions
E2bn	E2guardian	>= 5.4.0, <= 5.4.3r

References

http://www.openwall.com/lists/oss-security/2021/12/23/2Mailing List, Third Party Advisory
https://github.com/e2guardian/e2guardian/commit/eae46a7e2a57103aadca903c4a24cca94dc502a2Patch, Third Party Advisory
https://github.com/e2guardian/e2guardian/issues/707Exploit, Issue Tracking, Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/09/msg00010.html
http://www.openwall.com/lists/oss-security/2021/12/23/2Mailing List, Third Party Advisory
https://github.com/e2guardian/e2guardian/commit/eae46a7e2a57103aadca903c4a24cca94dc502a2Patch, Third Party Advisory
https://github.com/e2guardian/e2guardian/issues/707Exploit, Issue Tracking, Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/09/msg00010.html

Timeline

Published: Dec 23, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-44273?

How severe is CVE-2021-44273?

CVE-2021-44273 has a CVSS score of 7.4/10 (HIGH severity). The EPSS model estimates a 0.96% probability of exploitation in the next 30 days.

How do I fix CVE-2021-44273?

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-2021-44273?

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

Scan your code now

Source: NVD / NIST