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Nagios XiApplication · Nagios

CVE-2021-47695

MEDIUM · 5.4 CVSS v3.1 Published 2025-10-30
Fix available
A fix is available. Upgrade to 5.8.0 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Nagios XI versions prior to 5.8.0 are vulnerable to stored cross-site scripting (XSS) via the My Tools page. 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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Nagios XI versions prior to 5.8.0 contain a stored cross-site scripting (XSS) vulnerability in the My Tools page. The application fails to properly validate or escape user-supplied input, allowing attackers to inject malicious scripts that persist and execute in victims' browsers when the page is accessed.

MitigationUpgrade to Nagios XI version 5.8.0 or later. Until upgraded, implement input validation and output encoding on the My Tools page to neutralize malicious script injection.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Nagios XiApplication
Affected:< 5.8.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Nagios XI installation version
    Log into the Nagios XI administration interface and navigate to the 'About' or 'System Information' page typically found under Admin > System Information. Alternatively, check the version file at /usr/local/nagiosxi/etc/xi-sys.cfg or run 'rpm -q nagiosxi' if installed via RPM.
    Affected if The displayed version number is lower than 5.8.0 (for example, 5.7.0, 5.6.0, 5.5.0, etc.)
  2. Verify My Tools page accessibility
    Navigate to the 'My Tools' page in the Nagios XI web interface, usually found under the 'Tools' or 'My Tools' menu item in the navigation bar.
    Affected if The page loads successfully and accepts user input in any form fields present (such as name, description, or custom tool configuration fields).
  3. Inspect stored content on My Tools page for injected scripts
    View the source HTML of the My Tools page by right-clicking and selecting 'View Page Source', or use browser developer tools to inspect form fields and saved entries. Look for unescaped HTML tags or JavaScript code in the page content.
    Affected if User-supplied input appears in the page source without proper encoding (for example, raw <script> tags, event handlers like onload=, or unescaped quotes in HTML attributes).

You are affected if Nagios XI version is below 5.8.0 and the My Tools page is accessible with unsanitized user input present in the page.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.8.0 or later
Fixed in 5.8.0
Interim mitigation

Upgrade to Nagios XI version 5.8.0 or later. Until upgraded, implement input validation and output encoding on the My Tools page to neutralize malicious script injection.

Recommended fix Moderate confidence

Nagios XI 5.8.0 or later

  1. Verify current Nagios XI version by navigating to Admin > System Information > System Details
  2. Download Nagios XI 5.8.0 or later from the official Nagios website (www.nagios.com)
  3. Back up the current Nagios XI installation and database before proceeding
  4. Run the Nagios XI upgrade installer following official upgrade documentation
  5. After upgrade, verify the My Tools page input fields properly sanitize user-supplied content
  6. Confirm the version has been updated to 5.8.0 or later in Admin > System Information
Caveat Review Nagios XI 5.8.0 release notes for any configuration or feature changes that may affect existing setups

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Nagios Xi Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-47695 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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