---
id: CVE-2021-25299
title: Nagios XI version xi-5.7.5 is affected by cross-site scripting (XSS)
summary: >-
  Nagios XI version xi-5.7.5 is affected by cross-site scripting (XSS). The
  vulnerability exists in the file /usr/local/nagiosxi/html/admin/sshterm.php
  due to improper sanitization of user-controlled input. A maliciously crafted
  URL, when …
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'
cwe:
  - CWE-79
vendor: nagios
product: nagios_xi
affected:
  - nagios_xi = 5.7.5
published: '2021-02-15'
updated: '2026-07-05'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-25299'
references:
  - url: >-
      http://packetstormsecurity.com/files/161561/Nagios-XI-5.7.5-Remote-Code-Execution.html
    label: cve@mitre.org
  - url: 'https://assets.nagios.com/downloads/nagiosxi/versions.php'
    label: cve@mitre.org
  - url: 'https://github.com/fs0c-sh/nagios-xi-5.7.5-bugs/blob/main/README.md'
    label: cve@mitre.org
  - url: 'http://nagios.com'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      http://packetstormsecurity.com/files/161561/Nagios-XI-5.7.5-Remote-Code-Execution.html
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://assets.nagios.com/downloads/nagiosxi/versions.php'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/fs0c-sh/nagios-xi-5.7.5-bugs/blob/main/README.md'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - exploit-available
epss: 0.9776
epssPercentile: 0.99904
ingestedAt: '2026-07-05T00:59:25.820Z'
exploits:
  nuclei:
    - CVE-2021-25299
  checkedAt: '2026-09-25T08:20:38.338Z'
exploitAvailable: true
---

## Overview

Nagios XI version xi-5.7.5 is affected by cross-site scripting (XSS). The vulnerability exists in the file /usr/local/nagiosxi/html/admin/sshterm.php due to improper sanitization of user-controlled input. A maliciously crafted URL, when clicked by an admin user, can be used to steal his/her session cookies or it can be chained with the previous bugs to get one-click remote command execution (RCE) on the Nagios XI server.

## Affected

- `nagios_xi = 5.7.5`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.