CVE-2023-33176
Blind SSRF When Uploading Presentation in BigBlueButton
CVE-2023-33176 is a medium vulnerability (CVSS 4.8) in Bigbluebutton, published June 26, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.47%, the 40th percentile. No source names a fixed version.
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
4.8
Blind SSRF When Uploading Presentation in 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.
- Record
CVE-2023-33176- CVSS 3.1
- 4.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L - Weakness
- CWE-918
- Updated
- 2026-11-02
EUVDEUVD-2023-37359
4.8
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.
- Record
EUVD-2023-37359- CVSS 3.1
- 4.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L - Updated
- 2026-11-03
NVD
4.8
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.
- Record
CVE-2023-33176- CVSS 3.1
- 4.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
OSV
4.8
Blind SSRF When Uploading Presentation in 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.
- Record
CVE-2023-33176- CVSS 3.1
- 4.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L - Weakness
- CWE-918
- Updated
- 2026-11-02
Affected products
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | aliases, published | EUVD |
| 2026-11-02 | created | CVE List, NVD, OSV |
References
github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-3q22-hph2-cff7
github.com/bigbluebutton/bigbluebutton/pull/18045
github.com/bigbluebutton/bigbluebutton/pull/18052
github.com/bigbluebutton/bigbluebutton/commit/43394dade595d0707384e4878357901537352415
github.com/bigbluebutton/bigbluebutton/commit/b18aff32e65a47f1eb2c800e86dcfc7a8fb05e71
github.com/CVEProject/cvelistV5/tree/main/cves/2023/33xxx/CVE-2023-33176.json
nvd.nist.gov/vuln/detail/CVE-2023-33176