Vulnerability 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.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Bigbluebutton | Bigbluebutton | < 2.2.6 |
Related Weaknesses (CWE)
References
- https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286PatchThird Party Advisory
- https://github.com/mclab-hbrs/BBB-POCExploitThird Party Advisory
- https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286PatchThird Party Advisory
- https://github.com/mclab-hbrs/BBB-POCExploitThird Party Advisory
FAQ
What is CVE-2020-12443?
CVE-2020-12443 is a vulnerability with a CVSS score of 9.8 (CRITICAL). 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 ../ sequenc...
How severe is CVE-2020-12443?
CVE-2020-12443 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2020-12443?
Check the references section above for vendor advisories and patch information. Affected products include: Bigbluebutton Bigbluebutton.