Path Traversal in Bigbluebutton
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.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.037 (89.2th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 89th percentile — 89.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.036 · newest: 0.037 · change: +0.001
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/mclab-hbrs/BBB-POC (Exploit, Third Party Advisory)
- github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df9… (Patch, Third Party Advisory)
Frequently asked questions
- What is CVE-2020-12443?
- CVE-2020-12443 is a critical-severity vulnerability in Bigbluebutton, classified under Path Traversal. CVSS score: 9.8/10. Published 2020-04-29.
- How severe is CVE-2020-12443?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2020-12443 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.