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No exploitation reportedFix available

CVE-2020-12443

No exploitation reported by the sources we read.

  • Published2020-04-29
  • Fixed in2.2.6
  • WeaknessCWE-22

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2020-04-2902:15CVE publishedNVD

Versions per branch

NVD
Bigbluebutton
BranchAffectedFixed in
2.2< 2.2.62.2.6

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Bigbluebutton to 2.2.6

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2020-04-29
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-hp96-66jq-q83w

Frequently asked questions

What is 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 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.

Is CVE-2020-12443 actively exploited?

Active exploitation of CVE-2020-12443 has not been confirmed. Its EPSS score was 3.7% on 2026-11-09, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-12443?

CVE-2020-12443 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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