Prtg Network MonitorApplication · Paessler

CVE-2018-19411

HIGH · 8.8 CVSS v3.0 Published 2018-11-21
Fix available
A fix is available. Upgrade to 18.2.40.1683 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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 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.

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 versions before 18.2.40.1683 contain an improper authorization vulnerability in the /api/addusers endpoint. An authenticated user with only read-only permissions can send a crafted HTTP request to create new user accounts with full administrative privileges, effectively bypassing the application's role-based access control checks.

MitigationUpgrade PRTG Network Monitor to version 18.2.40.1683 or later. If immediate patching is not possible, restrict network access to the /api/addusers endpoint and monitor for unauthorized user creation events.

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:L/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. Identify installed PRTG version
    Access the PRTG web interface and navigate to Setup > About > License, or check the version displayed on the login page. Alternatively, check the version from the installer or program files.
    Affected if The installed version is lower than 18.2.40.1683
  2. Verify read-only user accounts exist
    In the PRTG web interface, go to Setup > Account Settings > User Accounts and review the list of users. Note which users have the "Read Only" or "Read Only User" role assigned.
    Affected if Any read-only user accounts exist in the system
  3. Check for unauthorized administrative accounts
    In the PRTG web interface, go to Setup > Account Settings > User Accounts and examine all accounts. Look for administrator-level accounts that were not created by known legitimate administrators.
    Affected if There are administrative user accounts that cannot be traced to authorized creation by a proper administrator
  4. Review user audit logs for account creation
    In the PRTG web interface, go to Setup > System Administration > History or Logs. Search for events related to user account creation, specifically those performed by read-only users.
    Affected if Any user account creation events were performed by users with only read-only permissions
  5. Inspect HTTP access to the addusers API endpoint
    Review web server logs or proxy logs for POST requests to /api/addusers. Check the source IP and authenticated user associated with these requests.
    Affected if HTTP POST requests to /api/addusers were made by users who only have read-only permissions

A user is affected if they are running PRTG Network Monitor version lower than 18.2.40.1683 and have read-only users who were able to create administrative accounts through the /api/addusers endpoint.

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.

From vendor data
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 /api/addusers endpoint and monitor for unauthorized user creation events.

Fix this in Prtg Network Monitor Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

Scan for this in your stack

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dbcve dependency scanner

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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-2018-19411 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