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.

Paessler PRTG Network Monitor before version 26.2.120.1449 is affected by a reflected Cross-Site Scripting (XSS) vulnerability. When a request is made for a non-existent resource ending in \".htm\", the web interface returns an HTTP 403 \"Forbidden Path\" error page that echoes the requested URL path into the HTML response body without proper output encoding or sanitization.

An unauthenticated, remote attacker can craft a URL containing an HTML/JavaScript payload in the path (e.g. https:////welcome.htm) and, once a victim with an active PRTG session opens the crafted link, execute arbitrary JavaScript in the security context of the PRTG web interface. Because the PRTG session cookie is not protected with the HttpOnly attribute, successful exploitation allows the attacker to read and exfiltrate the victim's session cookie, potentially leading to session hijacking.

PRTG Network Monitor before 23.1.82 allows remote attackers to write to files via the HTTP XML/REST Sensor.

PRTG Network Monitor before 23.1.82 allows remote attackers to write to files via the FTP Server Count Sensor.

Paessler PRTG Network Monitor before 25.4.114 allows XSS by an unauthenticated attacker via the filter parameter.

Paessler PRTG Network Monitor before 25.4.114 allows XSS by an unauthenticated attacker via the tag parameter.

Paessler PRTG Network Monitor before 25.4.114 allows Denial-of-Service (DoS) by an authenticated attacker via the Notification Contacts functionality.

Paessler PRTG Network Monitor contains a local file inclusion vulnerability that allows a remote, unauthenticated attacker to create users with read-write privileges (including administrator).

PRTG Network Monitor before 18.2.40.1683 allows an authenticated user with a read-only account to create another user with a read-write account (including administrator) via an HTTP request because /api/addusers doesn't check, or doesn't properly check, user rights.

PRTG Network Monitor before 18.3.44.2054 allows a remote authenticated attacker (with read-write privileges) to execute arbitrary code and OS commands with system privileges. When creating an HTTP Advanced Sensor, the user's input in the POST parameter 'proxyport' is mishandled. The attacker can craft an HTTP request and override the 'writeresult' command-line parameter for HttpAdvancedSensor.exe to store arbitrary data in an arbitrary place on the file system. For example, the attacker can create an executable file in the \Custom Sensors\EXE directory and execute it by creating EXE/Script Sensor.

An issue was discovered in PRTG Network Monitor before 18.2.39. An attacker who has access to the PRTG System Administrator web console with administrative privileges can exploit an OS command injection vulnerability (both on the server and on devices) by sending malformed parameters in sensor or notification management scenarios.

In Paessler PRTG Network Monitor 17.3.33.2830, it's possible to create a Map as a read-only user, by forging a request and sending it to the server.

PRTG Network Monitor 17.3.33.2830 allows remote authenticated administrators to execute arbitrary code by uploading a .exe file and then proceeding in spite of the error message.

PRTG Network Monitor version 17.3.33.2830 is vulnerable to stored Cross-Site Scripting on all group names created, related to incorrect error handling for an HTML encoded script.

PRTG Network Monitor version 17.3.33.2830 is vulnerable to reflected Cross-Site Scripting on error.htm (the error page), via the errormsg parameter.

XML external entity vulnerability in PRTG Network Monitor before 16.2.23.3077/3078 allows remote authenticated users to read arbitrary files by creating a new HTTP XML/REST Value sensor that accesses a crafted XML file.