Medium · published October 31, 2025
Nagios XI versions prior to < 2024R1.1 is vulnerable to a cross-site scripting (XSS) when a user visits the "missing page" (404) page after following a link from another website. The vulnerable component, page-missing.php, fails to properly validate or escape user-supplied input, allowing an attacker to craft a malicious link that, when visited by a victim, executes arbitrary JavaScript in the victim’s browser within the Nagios XI domain.
| Product | Versions | Fixed in |
|---|---|---|
| nagios/nagios_xi | < 2024 | 2024 |
| nagios/nagios_xi | all versions | — |
| nagios/nagios_xi | all versions | — |
| nagios/nagios_xi | all versions | — |