# CVE-2026-71555

## Summary

- **CVE ID:** CVE-2026-71555
- **Severity:** MEDIUM
- **CVSS Score:** 4.1 (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N)
- **CWE:** CWE-1022
- **Published:** Aug 6, 2026
- **Last Modified:** Aug 7, 2026

## Description

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.

## Affected Products

- THM-Health — PILOS (>= 2.1.0, < 4.14.1)

## References

- [CNA](https://github.com/THM-Health/PILOS/security/advisories/GHSA-j4wr-p8gh-xrw5)
- [CNA](https://github.com/THM-Health/PILOS/commit/b50f2bd07c4f4a7d6a9981578238ae3579275d81)
- [CNA](https://github.com/THM-Health/PILOS/releases/tag/v4.14.1)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.17%
- **EPSS Percentile:** 6.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._