High severity · published Sep 24, 2026
CVE-2026-4638
Plaintext Password Disclosure via VBScript Sensor Error Message in Paessler PRTG Network Monitor
7.1
CVSS
0.3%
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 23% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PN
PRTG Network Monitor · Paessler GmbH
before 26.2.120.1449 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-4638
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-4638
paessler.freshdesk.com
https://paessler.freshdesk.com/en/support/solutions/articles/76000088640
r.sec-consult.com
https://r.sec-consult.com/paessler
www.paessler.com
https://www.paessler.com/de/download/
www.paessler.com
https://www.paessler.com/prtg/prtg-network-monitor
More from PRTG Network Monitor
5.1
CVE-2026-4637
Reflected Cross-Site Scripting via URL Path in Paessler PRTG Network Monitor
