# CVE-2026-71555 — THM-Health PILOS

> As of 2026-08-06, CVE-2026-71555 is a MEDIUM-severity vulnerability in THM-Health PILOS, CVSS v3.1 4.1. No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-71555 as of 2026-08-06; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-08-06

## 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](https://cwe.mitre.org/data/definitions/1022.html). 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 2026-08-09.

**Vendor advisory and patch**

- [github.com](https://github.com/THM-Health/PILOS/security/advisories/GHSA-j4wr-p8gh-xrw5)

**Other references**

- [github.com](https://github.com/THM-Health/PILOS/commit/b50f2bd07c4f4a7d6a9981578238ae3579275d81)
- [github.com (v4.14)](https://github.com/THM-Health/PILOS/releases/tag/v4.14.1)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-71555
Full detection coverage and IOCs for threats exploiting CVE-2026-71555 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp