# CVE-2020-12443: Path traversal in n/a

> Remote attackers can read arbitrary files and escalate privileges via directory traversal in BigBlueButton due to case-insensitive NGINX configuration handling.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Apr 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-hp96-66jq-q83w

## What is CVE-2020-12443?

CVE-2020-12443 is a critical path traversal vulnerability in n/a, published on 29 Apr 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

BigBlueButton before 2.2.6 allows remote attackers to read arbitrary files because the presfilename (lowercase) value can be a .pdf filename while the presFilename (mixed case) value has a ../ sequence. This can be leveraged for privilege escalation via a directory traversal to bigbluebutton.properties. NOTE: this issue exists because of an ineffective mitigation to CVE-2020-12112 in which there was an attempted fix within an NGINX configuration file, without considering that the relevant part of NGINX is case-insensitive.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2020-12443?

It affects 1 product.


Products: Bigbluebutton Bigbluebutton.

## How do I fix CVE-2020-12443?

No fix has been published for CVE-2020-12443 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-12443 being exploited?

There is no known exploitation of CVE-2020-12443 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2020-27602](https://insights.sbomify.com/CVE-2020-27602/): Other in n/a (critical 9.8)
- [CVE-2020-27605](https://insights.sbomify.com/CVE-2020-27605/): Code injection in n/a (critical 9.8)
- [CVE-2020-27613](https://insights.sbomify.com/CVE-2020-27613/): Hardcoded credentials in n/a (high 8.4)
- [CVE-2021-4143](https://insights.sbomify.com/CVE-2021-4143/): Cross-site Scripting (XSS) - Generic in bigbluebutton/bigbluebutton (high 8.1)
- [CVE-2025-61601](https://insights.sbomify.com/CVE-2025-61601/): BigBlueButton vulnerable to DoS via PollSubmitVote GraphQL mutation (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-12443 and fix it if it is affected.

What it is: CVE-2020-12443 is a critical path traversal vulnerability in n/a, published on 29 Apr 2020. 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-2020-12443 in the wild and no public exploit code.

Affected product: n/a. 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-2020-12443/ (Markdown: https://insights.sbomify.com/CVE-2020-12443/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-12443
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-12443
- OSV: https://osv.dev/vulnerability/CVE-2020-12443

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-12443/
Summaries are generated and may contain mistakes; the official description above is the record.