CVE-2026-4638: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-gh9q-9rjg-9rq2
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CWE-209
Published
Advisory Summary

CVE-2026-4638 is a HIGH security vulnerability vulnerability (CWE-209: Generation of Error Message Containing Sensitive Information) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product generates an error message that includes sensitive information about its environment, users, or associated data.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-4638 at a Glance

CVE Identifier CVE-2026-4638
GHSA Identifier GHSA-gh9q-9rjg-9rq2
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-209: Generation of Error Message Containing Sensitive Information
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-4638

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-4638, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-209: Generation of Error Message Containing Sensitive Information, where the product generates an error message that includes sensitive information about its environment, users, or associated data. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

References

NVD — CVE-2026-4638 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-4638
paessler.freshdesk.com/en/support/solution... WEB
https://paessler.freshdesk.com/en/support/solutions/articles/76000088640
r.sec-consult.com/paessler WEB
https://r.sec-consult.com/paessler
www.paessler.com/de/download WEB
https://www.paessler.com/de/download
www.paessler.com/prtg/prtg-network-m... WEB
https://www.paessler.com/prtg/prtg-network-monitor

Frequently Asked Questions

What is CVE-2026-4638?
CVE-2026-4638 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-209: Generation of Error Message Containing Sensitive Information.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-4638?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2026-4638?
CVE-2026-4638 is classified under CWE-209: 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 can I check Maven dependencies for CVE-2026-4638?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-gh9q-9rjg-9rq2",
  "modified" : "2026-09-24T12:31:23Z",
  "published" : "2026-09-24T12:31:23Z",
  "aliases" : [ "CVE-2026-4638" ],
  "details" : "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. \n\n\n\n\nAny 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.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-4638"
  }, {
    "type" : "WEB",
    "url" : "https://paessler.freshdesk.com/en/support/solutions/articles/76000088640"
  }, {
    "type" : "WEB",
    "url" : "https://r.sec-consult.com/paessler"
  }, {
    "type" : "WEB",
    "url" : "https://www.paessler.com/de/download"
  }, {
    "type" : "WEB",
    "url" : "https://www.paessler.com/prtg/prtg-network-monitor"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-209" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-24T11:16:45Z"
  }
}