CVE-2020-36856

Name: CVE-2020-36856
Creator: NVD / NIST
Published: 2025-10-30T22:15:38.123+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.4/10EPSS 2.05%

Last modified Jun 17, 2026

CVE-2020-36856 is a critical-severity vulnerability rated 9.4/10 on the CVSS scale. Nagios XI versions prior to 5.6.14 contain an authenticated remote command execution vulnerability in the CCM command_test.php script. Insufficient validation of the `address` parameter allows an authenticated user with access to the Core Config Manager to inject shell metacharacters that are incorporated into backend command invocations. EPSS estimates a 2.05% chance of exploitation in the next 30 days.

Description

Nagios XI versions prior to 5.6.14 contain an authenticated remote command execution vulnerability in the CCM command_test.php script. Insufficient validation of the `address` parameter allows an authenticated user with access to the Core Config Manager to inject shell metacharacters that are incorporated into backend command invocations. Successful exploitation enables arbitrary command execution with the privileges of the Nagios XI web application user and may be leveraged to execute commands on the underlying XI host, modify system configuration, or fully compromise the host.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS 4.0

9.4/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

2.05%

78.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-78

Affected Software

Vendor	Product	Versions
Nagios	Nagios Xi	< 5.6.14

References

https://www.nagios.com/changelog/nagios-xi/Release Notes
https://www.nagios.com/products/security/#nagios-xiRelease Notes
https://www.vulncheck.com/advisories/nagios-xi-authenticated-rce-command-test-php-via-addressThird Party Advisory

Timeline

Published: Oct 30, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2020-36856?

How severe is CVE-2020-36856?

CVE-2020-36856 has a CVSS score of 9.4/10 (CRITICAL severity). The EPSS model estimates a 2.05% probability of exploitation in the next 30 days.

How do I fix CVE-2020-36856?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-36856?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST