Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 25 Feb 2025.
Prtg Network MonitorApplication · Paessler

CVE-2018-19410

CRITICAL · 9.8 CVSS v3.1 Published 2018-11-21
Fix available
A fix is available. Upgrade to 18.2.40.1683 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild High EPSS Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
PRTG Network Monitor before 18.2.40.1683 allows remote unauthenticated attackers to create users with read-write privileges (including administrator). A remote unauthenticated user can craft an HTTP request and override attributes of the 'include' directive in /public/login.htm and perform a Local File Inclusion attack, by including /api/addusers and executing it. By providing the 'id' and 'users' parameters, an unauthenticated attacker can create a user with read-write privileges (including administrator).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

PRTG Network Monitor before 18.2.40.1683 contains a critical authentication bypass vulnerability where unauthenticated attackers can craft HTTP requests to override the 'include' directive in /public/login.htm, enabling Local File Inclusion to execute /api/addusers. This allows remote attackers to create administrative users with read-write privileges via the 'id' and 'users' parameters.

MitigationUpgrade PRTG Network Monitor to version 18.2.40.1683 or later. If immediate patching is not possible, restrict network access to the PRTG interface to trusted IPs only as a temporary compensating control.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Prtg Network MonitorApplication
Affected:< 18.2.40.1683

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify PRTG Network Monitor is installed
    Check for PRTG installation by looking in Program Files for 'PRTG Network Monitor' folder, or check Windows Services for 'PRTG' services, or access the web interface on port 80/443
    Affected if PRTG Network Monitor is found on the system
  2. Determine installed PRTG version
    Open the PRTG web interface and check the version displayed on the login page or in 'Setup' > 'System Administration' > 'About PRTG', or check the version in the program's executable properties
    Affected if The version number is lower than 18.2.40.1683
  3. Inspect for unauthorized user accounts
    Log into PRTG as an administrator, navigate to 'Setup' > 'Account Settings' > 'User Management' or 'Users', and review all accounts for unknown or suspicious usernames with Administrator or Read-Write privileges
    Affected if There are user accounts that were not created by your organization or that have elevated privileges you did not assign
  4. Check network exposure of PRTG web interface
    Determine if the PRTG web server (ports 80, 443, or configured custom ports) is accessible from untrusted networks by reviewing firewall rules or performing a port scan from an external IP
    Affected if The PRTG web interface is accessible from the internet or untrusted networks without IP restrictions

You are affected if PRTG Network Monitor is installed with a version lower than 18.2.40.1683 and the web interface is network-accessible, or if unauthorized administrator accounts exist in the system.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 18.2.40.1683 or later
Fixed in 18.2.40.1683
Interim mitigation

Upgrade PRTG Network Monitor to version 18.2.40.1683 or later. If immediate patching is not possible, restrict network access to the PRTG interface to trusted IPs only as a temporary compensating control.

Recommended fix High confidence

18.2.40.1683

  1. 1. Download PRTG Network Monitor version 18.2.40.1683 or later from the official Paessler website (www.paessler.com)
  2. 2. Back up the current PRTG configuration, database, and settings before performing the upgrade
  3. 3. Install or upgrade to version 18.2.40.1683 following the vendor's standard upgrade procedure
  4. 4. After upgrade, verify the new version is running by checking the PRTG web interface
  5. 5. Confirm that the /public/login.htm vulnerability is no longer exploitable
Caveat Review release notes for this version to check for any changes that may affect your monitoring setup

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Prtg Network Monitor Exploited in the wild — priority engagement
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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Scan for this in your stack

Free · runs locally
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-19410 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data