Known exploited vulnerability · CISA KEV

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.

CVE-2019-15949

Exploited in the wild. Fix this first.

CISA added it to the Known Exploited Vulnerabilities catalog on 2021-11-03: attackers are using it right now.

CISA KEV: Listed; Added 2021-11-03 · federal fix-by 2022-05-03
EPSS (30 days): 77%; Higher than 99.6% of CVEs · 2026-11-01
CVSS v3.1: 8.8 High; CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

What CISA says

Nagios XI Remote Code Execution Vulnerability

Apply updates per vendor instructions.

NVD description · published 2019-09-05

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.

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How to check if you are exposed to CVE-2019-15949

Find every Nagios XI system you or your clients run, including ones exposed to the internet. Those come first: CISA only lists flaws attackers are already using.
Compare each version with the fixed versions in the vendor advisory. Where no fix exists yet, apply the vendor’s mitigation or take the system off the internet.
Run a credentialed vulnerability scan to catch the systems you missed, then check that the next scan no longer reports CVE-2019-15949.

US federal agencies had to fix this by 2022-05-03. Everyone else should treat that deadline as a guide: if it has passed, this is overdue.

Affected versions

Versions the National Vulnerability Database lists as vulnerable to CVE-2019-15949. Check the vendor advisory for the exact fixed builds before you sign anything off.

Product	Vulnerable versions
Nagios XI	before 5.6.6

Timeline

2019-09-05 · Published in the National Vulnerability Database
2021-11-03 · Added to CISA's Known Exploited Vulnerabilities catalog, 790 days after it was published
2022-05-03 · Fix-by date for US federal agencies, passed 1,643 days ago

Weakness type

CWE-78

More exploited Nagios vulnerabilities

CISA lists 4 exploited Nagios vulnerabilities. The closest matches:

Keep going

Sources: CISA Known Exploited Vulnerabilities catalog (version 2026.10.30); EPSS data from FIRST.org; CVSS and descriptions from the NIST National Vulnerability Database. Checked 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.