CVE-2026-48549

Name of the Vulnerable Software and Affected Versions Nagios Core versions prior to 4.5.13 Nagios XI versions prior to 2026R1.5

Description A Cross-Site Request Forgery (CSRF) issue exists in the 'cmd.cgi' endpoint. When the Cookie header is missing, the double-submit cookie protection mechanism can be bypassed by providing identical values for the NagFormId and nagFormId variables within the POST body. This allows an attacker to execute Nagios commands using the privileges of a currently authenticated user.

Recommendations Update Nagios Core to version 4.5.13 or later. Update Nagios XI to version 2026R1.5 or later.