CVE-2020-36856: nagios nagios_xi OS Command Injection

Vulnerability summary

CVE-2020-36856 is a critical (CVSS 9.4) OS Command Injection vulnerability in nagios nagios_xi. EPSS estimates a 2.45% chance of exploitation in the next 30 days, higher than 84.2% of scored vulnerabilities.

Timeline

1. 30-10-2025
   PublishedVulnerability first disclosed.
2. 17-11-2025
   Last modifiedVulnerability information updated.

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.

• CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.