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XI vulnerability

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.

Published 31 Oct 2025Updated 1 Oct 20263 sources
CVSS 5.1
Overview Sources History

What happened

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.

Affected versions

XI: before 2024R1.1 (custom) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

  • Apply vendor-provided updates or mitigations.
  • Review affected product exposure and access logs.

Public PoC references

No public PoC reference has passed the current publication threshold.

CorrectionsReport an issue