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Actively exploited

CVE-2019-15949 Nagios XI Remote Code Execution Vulnerability

Nagios XI contains a remote code execution vulnerability in which a user can modify the check_plugin executable and insert malicious commands to execute as root.

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 3 Nov 2021.
  • Rated High severity (CVSS 8.8, scored by CISA).
  • It has been in the catalogue for 1,829 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

Nagios XI before 5.6.6 allows remote command execution as root. The exploit requires access to the server as the nagios user, or access as the admin user via the web interface. The getprofile.sh script, invoked by downloading a system profile (profile.php?cmd=download), is executed as root via a passwordless sudo entry; the script executes check_plugin, which is owned by the nagios user. A user logged into Nagios XI with permissions to modify plugins, or the nagios user on the server, can modify the check_plugin executable and insert malicious commands to execute as root.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Nagios XI. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply updates per vendor instructions.

    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 3 May 2022 to remediate. A sensible benchmark for everyone else.

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

Stay Ahead

More Exploited Nagios Flaws

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CVE-2021-25296Nagios XI OS Command InjectionAdded 18 Jan 2022CVE-2021-25297Nagios XI OS Command InjectionAdded 18 Jan 2022CVE-2021-25298Nagios XI OS Command InjectionAdded 18 Jan 2022

All 4 exploited Nagios vulnerabilities

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2019-15949
  3. CVE record: CVE-2019-15949
  4. FIRST EPSS
  5. github.com/jakgibb/nagiosxi-root-rce-exploit
  6. packetstormsecurity.com/files/156676/Nagios-XI-Authenticated-Remote-Command-Execution.html
  7. packetstormsecurity.com/files/162158/Nagios-XI-getprofile.sh-Remote-Command-Execution.html