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Vulnerability record · CVE-2023-33176 · published 26 June 2023

CVE-2023-33176: Bigbluebutton server-side request forgery (ssrf) vulnerability

Bigbluebutton · Bigbluebutton

BigBlueButton is an open source virtual classroom designed to help teachers teach and learners learn. In affected versions are affected by a Server-Side Request Forgery (SSRF) vulnerability. In an `insertDocument` API request the user is able to supply a URL from which the presentation should be downloaded. This URL was being used without having been successfully validated first. An update to the `followRedirect` method in the `PresentationUrlDownloadService` has been made to validate all URLs to be used for presentation download. Two new properties `presentationDownloadSupportedProtocols` and `presentationDownloadBlockedHosts` have also been added to `bigbluebutton.properties` to allow administrators to define what protocols a URL must use and to explicitly define hosts that a presentation cannot be downloaded from. All URLs passed to `insertDocument` must conform to the requirements of the two previously mentioned properties. Additionally, these URLs must resolve to valid addresses, and these addresses must not be local or loopback addresses. There are no workarounds. Users are advised to upgrade to a patched version of BigBlueButton.

6.5 CVSS 3.1 Medium EPSS 0.47% · top 61.6% CWE-918 · Server-side request forgery (SSRF)
6.5CVSS 3.1 base score
0.47%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
10References
17 Jun 2026Last modified by NVD

Description

BigBlueButton is an open source virtual classroom designed to help teachers teach and learners learn. In affected versions are affected by a Server-Side Request Forgery (SSRF) vulnerability. In an `insertDocument` API request the user is able to supply a URL from which the presentation should be downloaded. This URL was being used without having been successfully validated first. An update to the `followRedirect` method in the `PresentationUrlDownloadService` has been made to validate all URLs to be used for presentation download. Two new properties `presentationDownloadSupportedProtocols` and `presentationDownloadBlockedHosts` have also been added to `bigbluebutton.properties` to allow administrators to define what protocols a URL must use and to explicitly define hosts that a presentation cannot be downloaded from. All URLs passed to `insertDocument` must conform to the requirements of the two previously mentioned properties. Additionally, these URLs must resolve to valid addresses, and these addresses must not be local or loopback addresses. There are no workarounds. Users are advised to upgrade to a patched version of BigBlueButton.

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

Affected products

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

References

LinkTags
https://github.com/bigbluebutton/bigbluebutton/commit/43394dade595d0707384e4878357901537352415 Patch
https://github.com/bigbluebutton/bigbluebutton/commit/b18aff32e65a47f1eb2c800e86dcfc7a8fb05e71 Patch
https://github.com/bigbluebutton/bigbluebutton/pull/18045 Patch
https://github.com/bigbluebutton/bigbluebutton/pull/18052 Issue Tracking
https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-3q22-hph2-cff7 Vendor Advisory
https://github.com/bigbluebutton/bigbluebutton/commit/43394dade595d0707384e4878357901537352415 Patch
https://github.com/bigbluebutton/bigbluebutton/commit/b18aff32e65a47f1eb2c800e86dcfc7a8fb05e71 Patch
https://github.com/bigbluebutton/bigbluebutton/pull/18045 Patch
https://github.com/bigbluebutton/bigbluebutton/pull/18052 Issue Tracking
https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-3q22-hph2-cff7 Vendor 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-2023-33176), CISA KEV, FIRST EPSS (scores of 2026-09-30). This page is refreshed as NVD updates the record.