CVE-2026-55491
A remote, authenticated attacker can exploit multiple vulnerabilities in BigBlueButton to conduct a Cross-Site Scripting attack, bypass security measures and manipulate data.
CSIRTS triage
- What
- Multiple vulnerabilities in BigBlueButton enable authenticated attackers to conduct cross-site scripting attacks, bypass security measures, and manipulate data.
- Who is affected
- Authenticated users and remote attackers exploiting prior access to BigBlueButton deployments are affected.
- Urgency
- Medium urgency; vulnerabilities require authentication to exploit, limiting exposure compared to unauthenticated attacks.
- Action
- Update BigBlueButton to a patched version addressing CVE-2026-55491 and CVE-2026-55489.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.17% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 6% of all EPSS-scored CVEs.
Advisory coverage (2)
- medium[UPDATE] [medium] BigBlueButton: Multiple Vulnerabilitiescert-bund · 2026-08-21
- mediumCVE-2026-55491: BigBlueButton is an open-source virtual classroom. Prior to 3.0.29, BigBlueButton failed to es…nvd · 2026-08-20
External references
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[](https://www.csirts.com/cve/CVE-2026-55491)