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OpenAdvisories
High · 7.1 CVE-2026-4638 EUVD-2026-85847GHSA-gh9q-9rjg-9rq2

Plaintext Password Disclosure via VBScript Sensor Error Message in Paessler PRTG Network Monitor

Published Sep 24, 2026 · Updated Sep 24, 2026 · Assigned by SEC-VLab

Description

PRTG Network Monitor before version 26.2.120.1449 ships a demo EXE/Script sensor that multiplies two integer parameters using cscript.exe. If a non-numeric value is passed instead, cscript.exe raises a 'Type mismatch' runtime error that includes the offending parameter value in plaintext. PRTG provides a documented placeholder variable, %windowspassword, which resolves to the configured Windows/domain password used by PRTG and can be passed as a sensor parameter. 

Any PRTG user who is not restricted to read-only access and is permitted to create sensors (the default for non-read-only users) can pass %windowspassword as an argument to the demo VBScript sensor, triggering the type-mismatch error and causing PRTG to display the plaintext password in the sensor's error output.

Affected products

VendorProductAffectedFixed
Paessler PRTG Network Monitor < 26.2.120.1449 26.2.120.1449

Advisories 1

References