---
cve: "CVE-2026-55491"
severity: "MEDIUM"
cvss: 5.4
epss: "0.2%"
vendor: "bigbluebutton"
kev: false
exploited: false
published: "2026-08-20 22:17:22"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-23T15:10:51+02:00"
---

# CVE-2026-55491

> 5.4 MEDIUM · 🧪 PoC

## Beschreibung

BigBlueButton is an open-source virtual classroom. Prior to 3.0.29, BigBlueButton failed to escape meetingName in record-and-playback/screenshare/playback/index.html.erb when generating the screenshare playback format. A low-privileged user could store a crafted meeting name that embedded script content, and the script executed in another user's browser when that user replayed the recording. This issue is fixed in version 3.0.29.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Erforderlich | good |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Gering | warn |
| I Integrität | Gering | warn |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- a53f2b92022388bfa4109d3136d1f3a932404b1b (Commit)
- e9d0534de2f014d1903d8c54885ca6acd5758a69 (Commit)

## Referenzen

- <https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-57p5-c888-74f9>
- <https://github.com/bigbluebutton/bigbluebutton/commit/a53f2b92022388bfa4109d3136d1f3a932404b1b>
- <https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.29>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-55491) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_