CVE-2026-71555: THM-Health PILOS · Use of Web Link to Untrusted Target with window.opener Access
Affects THM-Health PILOSSource CVE Database V5
Not known to be exploited · CVSS 4.1 Medium : upgrade to 4.14.1 when convenient.
Data as of 5 Nov 2026, 00:01 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.14.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 6 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Upgrade PILOS and thm-health/PILOS to 4.14.1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| THM-HealthPILOS | Affected
| Fixed in
|
GitHubthm-health/PILOSpkg:github/thm-health/PILOSOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
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. Patch status is not explicitly confirmed but fixed in 4.14.1 per the description.
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.