Security advisory

{
  "id": "00e1038377c4666d443bbed2313d48e88cc66aa6cbe5aa275f9e4a72d9fce3f1",
  "url": "https://osv.dev/vulnerability/CVE-2020-12443",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2020-12443",
    "summary": "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.",
    "evidence": "osv:CVE-2020-12443",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2020-12443",
      "aliases": [
        "CVE-2020-12443"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/bigbluebutton/bigbluebutton",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "db26d517a066f90f614e45eaf0c3e288a6800e05"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.2.6"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.2.5",
            "v2.2.4",
            "v2.2.2",
            "v2.2.3",
            "v2.2.1",
            "v2.2.0",
            "2.2-rc-6",
            "2.2-rc-5",
            "2.2-rc-4",
            "2.2-beta-17",
            "2.2-beta-16",
            "2.2-beta-15",
            "2.2-beta-14",
            "2.2-beta-12",
            "2.2-beta-11",
            "2.2-beta-10",
            "2.2-beta-9",
            "2.2-beta-8",
            "2.2-beta-7",
            "2.2-beta-6",
            "2.2-beta-5",
            "2.2-beta-4",
            "2.2-beta-3",
            "2.2-beta-2",
            "dcs-2-a",
            "v0.9.0-beta",
            "v0.8",
            "v0.8rc2",
            "v0.8b4.0",
            "v0.8b4"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-12443.json"
          }
        }
      ],
      "modified": "2026-10-20T10:51:05.797821616Z",
      "provider": "osv",
      "references": [
        "https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df96984b3a4c57679a463",
        "https://github.com/mclab-hbrs/BBB-POC"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2020-12443",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 382468,
  "published_at": "2020-04-29T02:15:11.467+00:00"
}