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TI-2023-16353 Aliases CVE-2023-33176

Blind SSRF When Uploading Presentation in BigBlueButton

Priority LOW 29CWE-918Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00471 41st percentileScored 2026-11-07
Fix Fixed bigbluebutton (bigbluebutton): 2.6.9, 2.5.18

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
bigbluebuttonbigbluebutton2.6.0 to before 2.6.9; before 2.5.182.6.9, 2.5.18Patch availableCNA
  • bigbluebutton Vendorbigbluebutton Affected 2.6.0 to before 2.6.9; before 2.5.18 Fixed in 2.6.9, 2.5.18 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:*before 2.5.18; 2.6.0 to before 2.6.9Vulnerablebigbluebutton
  • cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:* Versions before 2.5.18; 2.6.0 to before 2.6.9 Vulnerable ·bigbluebutton

Remediation

  • Fix · CNA bigbluebutton (bigbluebutton) Fixed in 2.6.9, 2.5.18

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-33176

References

Patch 3

Advisory 1

Other 1

  • TI-2026-21873 BigBlueButton: Exposed ClamAV port enables Denial of Service CVSS 3.1HIGH 8.2
  • TI-2025-38047 BigBlueButton vulnerable to Chat DoS via invalid reactionEmojiId CVSS 3.1HIGH 7.5
  • TI-2025-38046 BigBlueButton vulnerable to DoS via PollSubmitVote GraphQL mutation CVSS 3.1HIGH 7.5
  • TI-2022-13109 Cross site scripting in username that will trigger by sending chat CVSS 3.1MEDIUM 6.5
  • TI-2020-09954 BigBlueButton before 2.2.6 allows remote attackers to read arbitrary files because the… CVSS 3.1CRITICAL 9.8
  • TI-2020-16722 BigBlueButton through 2.2.28 uses Ghostscript for processing of uploaded EPS documents… CVSS 3.1CRITICAL 9.8
See all 48 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences