CVE-2020-12443
highpriority · track · 40EPSS 0.037 · 90 %ileEUUSEPSS · scored 2026-10-23
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.5–9.8
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (2)
Products and version ranges known to be affected.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (8)
External citations — patches, advisories, analysis.
- https://github.com/bigbluebutton/bigbluebutton/commit/5ebdf5ca7718fc8bb3c08867edd150278e6a724c#diff-c7d77969a4547b5349e55c5466948a27R45Patchcnnvd
- https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df96984b3a4c57679a463cnnvd
- https://github.com/mclab-hbrs/BBB-POCcnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2020-12443cnnvd
- https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df96984b3a4c57679a463enisa_euvd
- https://github.com/mclab-hbrs/BBB-POCenisa_euvd
- https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df96984b3a4c57679a463PatchThird Party Advisorynvd
- https://github.com/mclab-hbrs/BBB-POCExploitThird Party Advisorynvd
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan