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Vulnerability record · CVE-2020-12443 · published 29 April 2020

CVE-2020-12443: Bigbluebutton path traversal vulnerability

Bigbluebutton · Bigbluebutton

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.

9.8 CVSS 3.1 Critical EPSS 3.7% · top 10.8% CWE-22 · Path traversal
9.8CVSS 3.1 base score, v2 7.5
3.7%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df96984b3a4c57679a463 PatchThird Party Advisory
https://github.com/mclab-hbrs/BBB-POC ExploitThird Party Advisory
https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df96984b3a4c57679a463 PatchThird Party Advisory
https://github.com/mclab-hbrs/BBB-POC ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2020-12443), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.