---
cve: "CVE-2026-71555"
severity: "MEDIUM"
cvss: 4.1
epss: "17%"
vendor: "THM-Health"
kev: false
exploited: false
published: "2026-08-06 22:18:32"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-12T00:46:47+02:00"
---

# CVE-2026-71555

> 4.1 MEDIUM · 🧪 PoC

## Beschreibung

PILOS (Platform for Interactive Live-Online Seminars) is a frontend for BigBlueButton. From 2.1.0 until 4.14.1, PILOS does not send a Cross-Origin-Opener-Policy response header, so pages opened by PILOS via a link that opens a new browsing context (e.g., target="_blank") retain a window.opener reference back to the originating PILOS tab. A malicious destination page reached this way can use window.opener to navigate or manipulate the original PILOS tab, a technique known as reverse tabnabbing, potentially redirecting an authenticated user to a phishing page that mimics PILOS. This issue is fixed in version 4.14.1.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/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 | Keine | good |
| I Integrität | Gering | warn |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- b50f2bd07c4f4a7d6a9981578238ae3579275d81 (Commit)
- 82791a0e73f47733897dfcf01d5a9b866889bb83 (Commit)

## Referenzen

- <https://github.com/THM-Health/PILOS/security/advisories/GHSA-j4wr-p8gh-xrw5>
- <https://github.com/THM-Health/PILOS/commit/b50f2bd07c4f4a7d6a9981578238ae3579275d81>
- <https://github.com/THM-Health/PILOS/releases/tag/v4.14.1>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-71555) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_