CVE-2021-34599

Name: CVE-2021-34599
Creator: NVD / NIST
Published: 2021-12-01T09:15:06.627+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.4/10EPSS 0.46%

Last modified Jun 17, 2026

CVE-2021-34599 is a high-severity vulnerability rated 7.4/10 on the CVSS scale. Affected versions of CODESYS Git in Versions prior to V1.1.0.0 lack certificate validation in HTTPS handshakes. CODESYS Git does not implement certificate validation by default, so it does not verify that the server provides a valid and trusted HTTPS certificate. EPSS estimates a 0.46% chance of exploitation in the next 30 days.

Description

Affected versions of CODESYS Git in Versions prior to V1.1.0.0 lack certificate validation in HTTPS handshakes. CODESYS Git does not implement certificate validation by default, so it does not verify that the server provides a valid and trusted HTTPS certificate. Since the certificate of the server to which the connection is made is not properly verified, the server connection is vulnerable to a man-in-the-middle attack.

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

0.46%

36.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-295

Affected Software

Vendor	Product	Versions
Codesys	Git	< 1.1.0.0

References

Timeline

Published: Dec 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-34599?

How severe is CVE-2021-34599?

CVE-2021-34599 has a CVSS score of 7.4/10 (HIGH severity). The EPSS model estimates a 0.46% probability of exploitation in the next 30 days.

How do I fix CVE-2021-34599?

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-2021-34599?

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

Scan your code now

Source: NVD / NIST