CVE-2023-33176

MEDIUM
Published Jun 26, 20233y ago · Modified Jun 17, 20262w ago
6.5 CVSS 3.1
Medium
Find Similar
Published Jun 26, 2023 3y ago
Last Modified Jun 17, 2026 2w ago

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 Details

Base Score
6.5
Exploitability
3.9
Impact
2.5
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Low
Integrity Low
Availability None

Threat Intelligence

No active exploitation signals — not in CISA KEV and no EPSS score yet.

Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-918 Server-Side Request Forgery (SSRF) Validation

Affected Products 2

VendorProductVersionRange
bigbluebuttonbigbluebutton* <2.5.18
bigbluebuttonbigbluebutton*≥2.6.0  –  <2.6.9

References 5

  • github.com https://github.com/bigbluebutton/bigbluebutton/commit/43394dade595d0707384e4878357901537352415
    Patch
  • github.com https://github.com/bigbluebutton/bigbluebutton/commit/b18aff32e65a47f1eb2c800e86dcfc7a8fb05e71
    Patch
  • github.com https://github.com/bigbluebutton/bigbluebutton/pull/18045
    Patch
  • github.com https://github.com/bigbluebutton/bigbluebutton/pull/18052
    Issue Tracking
  • github.com https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-3q22-hph2-cff7
    Vendor Advisory

Remediation

  • github.com https://github.com/bigbluebutton/bigbluebutton/commit/43394dade595d0707384e4878357901537352415
    Patch
  • github.com https://github.com/bigbluebutton/bigbluebutton/commit/b18aff32e65a47f1eb2c800e86dcfc7a8fb05e71
    Patch
  • github.com https://github.com/bigbluebutton/bigbluebutton/pull/18045
    Patch