CVE-2021-34599
Improper Certificate Validation in CODESYS Git
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Improper Certificate Validation in CODESYS Git
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.
- Record
CVE-2021-34599- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-295
- Updated
- 2026-11-02
EUVDEUVD-2021-21249
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.
- Record
EUVD-2021-21249- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-hgcw-m9r8-99rp
Affected versions of CODESYS Git in Versions prior to V1.1.0.0 lack certificate validation in...
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.
- Record
GHSA-hgcw-m9r8-99rp- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-295
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-34599- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - CVSS 2.0
- 5.8 Medium
AV:N/AC:M/Au:N/C:P/I:P/A:N - Weakness
- CWE-295
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-34599 is a high vulnerability (CVSS 7.4) in Codesys Git, published December 1, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.47%, the 41st percentile. No source names a fixed version.