# CVE-2020-5909: Security feature bypass in NGINX Controller

> Attackers can intercept agent installer downloads via Man-in-the-Middle attacks because TLS certificate verification is disabled in the NGINX Controller UI command.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 2 Jul 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-989x-v562-xr5m

## What is CVE-2020-5909?

CVE-2020-5909 is a medium-severity vulnerability in NGINX Controller, published on 2 Jul 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

In versions 3.0.0-3.5.0, 2.0.0-2.9.0, and 1.0.1, when users run the command displayed in NGINX Controller user interface (UI) to fetch the agent installer, the server TLS certificate is not verified.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2020-5909?

It affects 1 product.


Products: F5 Nginx Controller.

## How do I fix CVE-2020-5909?

No fix has been published for CVE-2020-5909 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-5909 being exploited?

There is no known exploitation of CVE-2020-5909 in the wild and no public exploit code.

## Other vulnerabilities in NGINX Controller

- [CVE-2020-27730](https://insights.sbomify.com/CVE-2020-27730/): Path traversal in NGINX Controller (critical 9.8)
- [CVE-2020-5901](https://insights.sbomify.com/CVE-2020-5901/): Cross-site scripting in NGINX Controller (critical 9.6)
- [CVE-2020-5900](https://insights.sbomify.com/CVE-2020-5900/): Cross-site request forgery in NGINX Controller (high 8.8)
- [CVE-2020-5863](https://insights.sbomify.com/CVE-2020-5863/): Missing authorization in NGINX Controller (high 8.6)
- [CVE-2020-5894](https://insights.sbomify.com/CVE-2020-5894/): Security feature bypass in NGINX Controller (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-5909 and fix it if it is affected.

What it is: CVE-2020-5909 is a medium-severity vulnerability in NGINX Controller, published on 2 Jul 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-5909 in the wild and no public exploit code.

Affected product: NGINX Controller. 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-2020-5909/ (Markdown: https://insights.sbomify.com/CVE-2020-5909/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-5909
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-5909
- OSV: https://osv.dev/vulnerability/CVE-2020-5909

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-5909/
Summaries are generated and may contain mistakes; the official description above is the record.