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BigBlueButton API checksum bypass via presentationUploadExternalUrl

Type: advisorySources: OSV

BigBlueButton is an open-source virtual classroom. Prior to 3.0.21, bbb-web checksum validation could be bypassed when a presentationUploadExternalUrl parameter was supplied to API request handling in CreateMeeting.java and ValidationService.java, allowing a user to send valid requests to some endpoints without a checksum. This issue is fixed in version 3.0.21.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-46353
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 03:25 UTC · Revision 1

Source evidence

BigBlueButton API checksum bypass via presentationUploadExternalUrl

core-osv · Original source

Published 16 Jul 2026, 18:06 UTC

BigBlueButton is an open-source virtual classroom. Prior to 3.0.21, bbb-web checksum validation could be bypassed when a presentationUploadExternalUrl parameter was supplied to API request handling in CreateMeeting.java and ValidationService.java, allowing a user to send valid requests to some endpoints without a checksum. This issue is fixed in version 3.0.21.

osv:CVE-2026-46353
Complete source record
{
  "id": "b5e36f1ec5fc9672f0f9c02a08480d6da43ff9f7d5b22867f30288e7385512d2",
  "url": "https://osv.dev/vulnerability/CVE-2026-46353",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "BigBlueButton API checksum bypass via presentationUploadExternalUrl",
    "summary": "BigBlueButton is an open-source virtual classroom. Prior to 3.0.21, bbb-web checksum validation could be bypassed when a presentationUploadExternalUrl parameter was supplied to API request handling in CreateMeeting.java and ValidationService.java, allowing a user to send valid requests to some endpoints without a checksum. This issue is fixed in version 3.0.21.",
    "evidence": "osv:CVE-2026-46353",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-46353",
      "aliases": [
        "CVE-2026-46353",
        "GHSA-43hc-5g2m-cqff"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/bigbluebutton/bigbluebutton",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "180cefe5727aea7493194223b1d9263f747a97ba"
                },
                {
                  "fixed": "36fd1b407488a0c56ce620b91184d5a8aea68b3d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "3.0.21"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "36fd1b407488a0c56ce620b91184d5a8aea68b3d"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "180cefe5727aea7493194223b1d9263f747a97ba"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v3.0.21"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.0.20",
            "v3.0.19",
            "v3.0.18",
            "v3.0.17",
            "v3.0.16",
            "v3.0.15",
            "v3.0.14",
            "v3.0.13",
            "v3.0.12",
            "v3.0.11",
            "v3.0.8",
            "v3.0.10",
            "v3.0.9",
            "v3.0.7",
            "v3.0.5",
            "v3.0.4",
            "v3.0.2",
            "v3.0.3",
            "v3.0.0",
            "v3.0.1",
            "v3.0.0-rc.4",
            "v3.0.0-rc.3",
            "v3.0.0-rc.2",
            "v3.0.0-rc.1",
            "3.0.0-rc.1",
            "v3.0.0-beta.7",
            "v3.0.0-beta.6",
            "v3.0.0-beta.5",
            "v3.0.0-beta.4",
            "v3.0.0-beta.3",
            "v3.0.0-beta.2",
            "v3.0.0-beta.1",
            "v3.0.0-alpha.7",
            "v3.0.0-alpha.6",
            "v3.0.0-alpha.4",
            "v3.0.0-alpha.3",
            "v3.0.0-alpha.2",
            "v3.0.0-alpha.1",
            "v2.4-beta-4",
            "v2.4-beta-3",
            "v2.4-beta-2",
            "v2.4-beta-1",
            "v2.4-alpha-1",
            "v2.3.1",
            "v2.3.0",
            "v2.3-rc-2",
            "v2.3-rc-1",
            "v2.3-beta-5",
            "v2.3-beta-4",
            "v2.3-beta-3",
            "v2.3-beta-2",
            "v2.3-beta-1",
            "v2.3-alpha-8",
            "v2.3-alpha-7",
            "v2.3-alpha-6",
            "v2.3-alpha-5",
            "v2.3-alpha-4",
            "v2.3-alpha-3",
            "v2.3-alpha-2",
            "v2.3-alpha-1",
            "2.2-rc-3",
            "2.2-rc-2",
            "2.2-rc-1",
            "2.2-beta-23",
            "2.2-beta-22",
            "2.2-beta-21",
            "2.2-beta-20",
            "2.2-beta-19",
            "2.2-beta-18",
            "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-2026-46353.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.944133761Z",
      "provider": "osv",
      "references": [
        "https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.21",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46353.json",
        "https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-43hc-5g2m-cqff",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-46353",
        "https://github.com/bigbluebutton/bigbluebutton/commit/36fd1b407488a0c56ce620b91184d5a8aea68b3d"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-284"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46353.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-46353",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 500020,
  "published_at": "2026-07-16T18:06:54.645+00:00"
}