CVE-2026-71555: Thm-Health Pilos

Medium severity, CVSS 4.1. EPSS: 0.3% chance of exploitation in the next 30 days.

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: from 2.1.0, before 4.14.1 (fixed in 4.14.1)

Published 2026-08-06. Last modified 2026-09-10.