PRTG Network Monitor: Generation of Error Message Containing Sensitive Information
CVE-2026-4638 is a high-severity generation of error message containing sensitive information vulnerability in PRTG Network Monitor from Paessler, with a CVSS 4.0 base score of 7.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 26.2.120.1449 as the first without the flaw, so updating PRTG Network Monitor to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.3% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update PRTG Network Monitor to 26.2.120.1449 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Paessler | PRTG Network Monitor | before 26.2.120.1449 | 26.2.120.1449 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- NoneThe attack does not depend on a particular deployment or configuration.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- NoneNo loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- NoneNo loss of availability on the vulnerable system.
- Confidentiality (other systems)
- NoneNo loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- NoneNo loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- NoneNo loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA.
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Generation of Error Message Containing Sensitive Information
The product generates an error message that includes sensitive information about its environment, users, or associated data.
How developers prevent this class of flaw
- Handle exceptions internally and do not display errors containing potentially sensitive information to a user.
- Use naming conventions and strong types to make it easier to spot when sensitive data is being used. When creating structures, objects, or other complex entities, separate the sensitive and non-sensitive data as much as possible.
- Debugging information should not make its way into a production release.
More Generation of Error Message Containing Sensitive Information vulnerabilities (CWE-209)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
References
Other references
Other vulnerabilities in PRTG Network Monitor
- 7.2 High severity
- 7.2 High severity
- 8.8 High severity
- 9.8 Critical severity
- 7.2 High severity
Recent Generation of Error Message Containing Sensitive Information vulnerabilities
- 7.7 High severity
- 7.1 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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