What’s Vulnerable › Vulnerabilities

CVE-2020-36866: Nagios XI < 5.7.3 XSS via Manage Users in Admin Interface

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-10-30 · updated 2026-10-18
• Weakness: CWE-79

Description

Nagios XI versions prior to 5.7.3 are vulnerable to cross-site scripting (XSS) via the Manage Users page of the Admin interface. 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.

Affected products

• Nagios XI: before 5.7.2 — fixed in 5.7.2

How to fix

Upgrade to a fixed version: Nagios XI 5.7.2. Check the vendor advisory for mitigations.

References

• https://www.nagios.com/changelog/nagios-xi/
• https://www.vulncheck.com/advisories/nagios-xi-xss-via-manage-users-in-admin-interface

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