# CVE-2021-36763: Path traversal in n/a

> An attacker can access unauthorized files or directories on the CODESYS V3 web server, leading to information disclosure.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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:** 3 Aug 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-w4jx-jw2g-xvqv

## What is CVE-2021-36763?

CVE-2021-36763 is a high-severity path traversal vulnerability in Codesys Control Runtime System Toolkit, published on 3 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In CODESYS V3 web server before 3.5.17.10, files or directories are accessible to External Parties.

Weakness: CWE-552 (Files or Directories Accessible to External Parties)

## Which versions are affected by CVE-2021-36763?

It affects 7 products.


Products: Codesys Control, Codesys Control Rte, Codesys Control Runtime System Toolkit, Codesys Control Win Sl, Codesys Embedded Target Visu Toolkit, Codesys Hmi, Codesys Remote Target Visu Toolkit.

## How do I fix CVE-2021-36763?

No fix has been published for CVE-2021-36763 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-36763 being exploited?

There is no known exploitation of CVE-2021-36763 in the wild and no public exploit code.

## Other vulnerabilities in Codesys Control Runtime System Toolkit

- [CVE-2021-33485](https://insights.sbomify.com/CVE-2021-33485/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-36763 and fix it if it is affected.

What it is: CVE-2021-36763 is a high-severity path traversal vulnerability in Codesys Control Runtime System Toolkit, published on 3 Aug 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-2021-36763 in the wild and no public exploit code.

Affected product: Codesys Control Runtime System Toolkit. 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-2021-36763/ (Markdown: https://insights.sbomify.com/CVE-2021-36763/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-36763
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-36763
- OSV: https://osv.dev/vulnerability/CVE-2021-36763

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-36763/
Summaries are generated and may contain mistakes; the official description above is the record.