# CVE-2021-34599: Improper Certificate Validation in CODESYS Git

> CODESYS Git fails to validate HTTPS certificates, allowing attackers to perform man-in-the-middle attacks to intercept or modify data.

- **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 1 Dec 2021
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-hgcw-m9r8-99rp

## What is CVE-2021-34599?

CVE-2021-34599 is a high-severity vulnerability in CODESYS Git, published on 1 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2021-34599?

It affects 1 product.


Products: Codesys Git.

## How do I fix CVE-2021-34599?

No fix has been published for CVE-2021-34599 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-34599 being exploited?

There is no known exploitation of CVE-2021-34599 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-34599 and fix it if it is affected.

What it is: CVE-2021-34599 is a high-severity vulnerability in CODESYS Git, published on 1 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-34599 in the wild and no public exploit code.

Affected product: CODESYS Git. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-34599/ (Markdown: https://insights.sbomify.com/CVE-2021-34599/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-34599
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-34599
- OSV: https://osv.dev/vulnerability/CVE-2021-34599

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-34599/
Summaries are generated and may contain mistakes; the official description above is the record.