CVE-2018-19410 Paessler PRTG Network Monitor Local File Inclusion Vulnerability
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).
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 4 Feb 2025.
- Rated Critical severity (CVSS 9.8, scored by CISA).
- It has been in the catalogue for 640 days. Systems still unpatched now have almost certainly been scanned for it.
What It Is
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).
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for Paessler PRTG Network Monitor. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
Fix it
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Vulnerability Management - 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
Not Sure If You Are Exposed?
Our attack surface and vulnerability teams can check your internet-facing estate for CVE-2018-19410 and every other exploited flaw on the list.