---
id: CVE-2026-71555
title: >-
  PILOS (Platform for Interactive Live-Online Seminars) is a frontend for
  BigBlueButton
summary: >-
  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 browsi…
severity: medium
cvss: 4.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N'
cwe:
  - CWE-1022
published: '2026-08-06'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T20:42:39.707'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-71555'
references:
  - url: >-
      https://github.com/THM-Health/PILOS/commit/b50f2bd07c4f4a7d6a9981578238ae3579275d81
    label: security-advisories@github.com
  - url: 'https://github.com/THM-Health/PILOS/releases/tag/v4.14.1'
    label: security-advisories@github.com
  - url: >-
      https://github.com/THM-Health/PILOS/security/advisories/GHSA-j4wr-p8gh-xrw5
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00293
epssPercentile: 0.1948
ingestedAt: '2026-09-10T21:05:53.595Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.