Nagios XI versions prior to < 2024R1.1.2 are vulnerable to a reflected cross-site scripting (XSS) via the login page when accessed with older web browsers. Insufficient validation or escaping of user-supplied input reflected by the login page can allow 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 origin. The issue is observable under legacy browser behaviors; modern browsers may mitigate some vectors.
Conclusion & alert: CVE-2024-13993 is rated Moderate Risk (46.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.74%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-05-26 | 0.56% | 0.74% | +0.19% |
| 2 | 2026-04-09 | 0.33% | 0.56% | +0.23% |
| 3 | 2026-03-28 | — | 0.33% | — |
Full EPSS history (8 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.1 | 4.0 | MEDIUM |
|
— | — | [email protected] |
| 6.1 | 3.1 | MEDIUM |
|
2.8 | 2.7 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| nagios | nagios_xi | < 2024 | cpe:2.3:a:nagios:nagios_xi:*:*:*:*:*:*:*:* |
| nagios | nagios_xi | 2024 | cpe:2.3:a:nagios:nagios_xi:2024:r1:*:*:*:*:*:* |
| nagios | nagios_xi | 2024 | cpe:2.3:a:nagios:nagios_xi:2024:r1.0.1:*:*:*:*:*:* |
| nagios | nagios_xi | 2024 | cpe:2.3:a:nagios:nagios_xi:2024:r1.1:*:*:*:*:*:* |
| nagios | nagios_xi | 2024 | cpe:2.3:a:nagios:nagios_xi:2024:r1.1.1:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://www.nagios.com/changelog/nagios-xi/ | Release Notes |
| https://www.nagios.com/products/security/#nagios-xi | Vendor Advisory |
| https://www.vulncheck.com/advisories/nagios-xi-reflected-xss-via-login-page-on-older-browsers | Third Party Advisory |