What is CVE-2026-71555?
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.
The record classifies CVE-2026-71555 under weakness class CWE-1022. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs a user to take an action first. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 60 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 4.1 — MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N - CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 2.1/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-08-06
Is CVE-2026-71555 being exploited?
It currently carries a trending score of 29 in the Threadlinqs vulnerability feed.
Affected products and versions
- THM-Health: PILOS
How to fix CVE-2026-71555
No vendor patch reference has been recorded for CVE-2026-71555 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-71555
No threat campaign in the Threadlinqs corpus currently references CVE-2026-71555, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org. Last verified by Threadlinqs on .