CVE-2026-4638Plaintext Password Disclosure via VBScript Sensor Error Message in Paessler PRTG Network Monitor

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.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• https://r.sec-consult.com/paessler third-party-advisory
• https://paessler.freshdesk.com/en/support/solutions/articles/76000088640 vendor-advisory
• https://www.paessler.com/de/download/ patch
• https://www.paessler.com/prtg/prtg-network-monitor product