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Actively exploited

CVE-2018-9276 Paessler PRTG Network Monitor OS Command Injection Vulnerability

Paessler PRTG Network Monitor contains an OS command injection vulnerability that allows an attacker with administrative privileges to execute commands via the PRTG System Administrator web console.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch urgentlyCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 4 Feb 2025.
  • Rated High severity (CVSS 7.2, scored by CISA).
  • It has been in the catalogue for 640 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

An issue was discovered in PRTG Network Monitor before 18.2.39. An attacker who has access to the PRTG System Administrator web console with administrative privileges can exploit an OS command injection vulnerability (both on the server and on devices) by sending malformed parameters in sensor or notification management scenarios.

From Watch to Action

What To Do Now

  1. 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. 2

    Fix it

    Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

    Vulnerability Management
  3. 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. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated high, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 25 Feb 2025 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

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CVE-2018-19410Paessler PRTG Network Monitor Local File Inclusion VulnerabilityAdded 4 Feb 2025

All 2 exploited Paessler vulnerabilities

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2018-9276
  3. CVE record: CVE-2018-9276
  4. FIRST EPSS
  5. paessler.com/prtg/history/prtg-18#18.2.39
  6. packetstormsecurity.com/files/148334/PRTG-Command-Injection.html
  7. exploit-db.com/exploits/46527/
  8. securityfocus.com/archive/1/542103/100/0/threaded
  9. packetstormsecurity.com/files/161183/PRTG-Network-Monitor-Remote-Code-Execution.html