CVE-2026-71555: CWE-1022: Use of Web Link to Untrusted Target with window.opener Access in THM-Health PILOS
PILOS, a frontend for BigBlueButton, versions from 2.1.0 up to but not including 4.14.1, does not send a Cross-Origin-Opener-Policy header. This allows pages opened with target="_blank" to retain a window.opener reference to the original PILOS tab. A malicious page opened this way can manipulate the original tab via reverse tabnabbing, potentially redirecting authenticated users to phishing pages. The issue is fixed in version 4.14.1.
AI Analysis
Technical Summary
PILOS versions >=2.1.0 and <4.14.1 lack the Cross-Origin-Opener-Policy response header, enabling reverse tabnabbing attacks through window.opener references in new browsing contexts opened by links with target="_blank". This vulnerability (CWE-1022) allows a malicious destination page to manipulate the original PILOS tab, potentially redirecting authenticated users to phishing pages that mimic PILOS. The vulnerability is addressed in version 4.14.1.
Potential Impact
An attacker controlling a linked page can use the window.opener reference to navigate or manipulate the original PILOS tab, potentially redirecting authenticated users to phishing pages. This can lead to user deception but does not directly compromise confidentiality or availability of PILOS itself. The CVSS score is 4.1 (medium severity), reflecting limited impact with user interaction required.
Mitigation Recommendations
Upgrade PILOS to version 4.14.1 or later, where the Cross-Origin-Opener-Policy header is properly set to prevent reverse tabnabbing. No other official remediation or temporary fixes are documented. Patch status is confirmed by the version fix information.
CVE-2026-71555: CWE-1022: Use of Web Link to Untrusted Target with window.opener Access in THM-Health PILOS
Description
PILOS, a frontend for BigBlueButton, versions from 2.1.0 up to but not including 4.14.1, does not send a Cross-Origin-Opener-Policy header. This allows pages opened with target="_blank" to retain a window.opener reference to the original PILOS tab. A malicious page opened this way can manipulate the original tab via reverse tabnabbing, potentially redirecting authenticated users to phishing pages. The issue is fixed in version 4.14.1.
CVSS v3.1
Score 4.1medium
Affected software
pkg:github/thm-health/PILOSRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
PILOS versions >=2.1.0 and <4.14.1 lack the Cross-Origin-Opener-Policy response header, enabling reverse tabnabbing attacks through window.opener references in new browsing contexts opened by links with target="_blank". This vulnerability (CWE-1022) allows a malicious destination page to manipulate the original PILOS tab, potentially redirecting authenticated users to phishing pages that mimic PILOS. The vulnerability is addressed in version 4.14.1.
Potential Impact
An attacker controlling a linked page can use the window.opener reference to navigate or manipulate the original PILOS tab, potentially redirecting authenticated users to phishing pages. This can lead to user deception but does not directly compromise confidentiality or availability of PILOS itself. The CVSS score is 4.1 (medium severity), reflecting limited impact with user interaction required.
Mitigation Recommendations
Upgrade PILOS to version 4.14.1 or later, where the Cross-Origin-Opener-Policy header is properly set to prevent reverse tabnabbing. No other official remediation or temporary fixes are documented. Patch status is confirmed by the version fix information.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-06T21:24:15.376Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a750711bf8831d5395f5e28
Added to database: 08/06/2026, 22:13:37 UTC
Last enriched: 08/06/2026, 22:27:16 UTC
Last updated: 08/06/2026, 23:17:31 UTC
Views: 5
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