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 set the Cross-Origin-Opener-Policy header. This allows pages opened with target="_blank" to retain a window.opener reference, enabling reverse tabnabbing attacks where a malicious page can manipulate the original PILOS tab. 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, which causes pages opened in new browsing contexts (e.g., via target="_blank") to maintain a window.opener reference to the original PILOS tab. This enables reverse tabnabbing, where a malicious destination page can use window.opener to redirect or manipulate the original tab, potentially leading to phishing attacks. The vulnerability is addressed in version 4.14.1.
Potential Impact
An attacker controlling a linked page opened from PILOS can manipulate the original PILOS tab via window.opener, potentially redirecting authenticated users to phishing pages that mimic PILOS. This can lead to user deception and credential theft. There is no direct confidentiality or availability impact reported.
Mitigation Recommendations
Upgrade PILOS to version 4.14.1 or later, where the Cross-Origin-Opener-Policy header is properly set to prevent window.opener access from untrusted targets. No other official remediation details are provided. Patch status is not explicitly confirmed but fixed in 4.14.1 per the description.
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 set the Cross-Origin-Opener-Policy header. This allows pages opened with target="_blank" to retain a window.opener reference, enabling reverse tabnabbing attacks where a malicious page can manipulate the original PILOS tab. The issue is fixed in version 4.14.1.
CVSS v3.1
Score 4.1medium
Affected software
THM-Health
PILOS
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, which causes pages opened in new browsing contexts (e.g., via target="_blank") to maintain a window.opener reference to the original PILOS tab. This enables reverse tabnabbing, where a malicious destination page can use window.opener to redirect or manipulate the original tab, potentially leading to phishing attacks. The vulnerability is addressed in version 4.14.1.
Potential Impact
An attacker controlling a linked page opened from PILOS can manipulate the original PILOS tab via window.opener, potentially redirecting authenticated users to phishing pages that mimic PILOS. This can lead to user deception and credential theft. There is no direct confidentiality or availability impact reported.
Mitigation Recommendations
Upgrade PILOS to version 4.14.1 or later, where the Cross-Origin-Opener-Policy header is properly set to prevent window.opener access from untrusted targets. No other official remediation details are provided. Patch status is not explicitly confirmed but fixed in 4.14.1 per the description.
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
Threat ID: 6a750711bf8831d5395f5e28
Added to database: 08/06/2026, 22:13:37 UTC
Last enriched: 08/14/2026, 16:09:38 UTC
Last updated: 09/19/2026, 22:01:37 UTC
Views: 62
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