Nagios XI < 5.8.0 Core Config Manager (CCM) XSS via Templates Pages

Advisories

severity: medium
date: October 30, 2025
Affecting: XI < 5.8.0
CCM < 3.1.0
CVE: CVE-2021-47689
CWE: CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')
CVSS: 5.1
CVSS V4 Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
References: Nagios XI Changelog
Credit: Matthew Aberegg
Description: The Core Config Manager (CCM) in Nagios XI versions prior to CCM 3.1.0 / Nagios XI 5.8.0 contains a cross-site scripting (XSS) vulnerability in the Templates pages, specifically in the UI logic that renders and handles the Active/Actions buttons. Insufficient validation or escaping of user-supplied input may allow an attacker to inject and execute arbitrary script in the context of a victim's browser.