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Nagios XiApplication · Nagios

CVE-2021-47690

MEDIUM · 5.4 CVSS v3.1 Published 2025-10-30
Fix available
A fix is available. Upgrade to 5.8.2 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
The Core Config Manager (CCM) in Nagios XI versions prior to CCM 3.1.1 / Nagios XI 5.8.2 contains multiple cross-site scripting (XSS) vulnerabilities in Overlay modals. 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

Multiple cross-site scripting (XSS) vulnerabilities exist in the Core Config Manager (CCM) overlay modals of Nagios XI. The vulnerabilities stem from insufficient validation and escaping of user-supplied input, allowing attackers to inject and execute arbitrary JavaScript in the context of a victim's browser.

MitigationUpgrade to Nagios XI CCM 3.1.1 / XI 5.8.2 or later, which includes proper input validation and output encoding fixes for the affected overlay modals.

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:< 5.8.2

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 installed Nagios XI version
    Run the command: cat /usr/local/nagiosxi/var/nagiosxi.ver or check the Nagios XI admin web interface under Admin > System Information > System Details
    Affected if The version shown is earlier than 5.8.2 (for example, 5.8.0, 5.7.x, 5.6.x, etc.)
  2. Confirm CCM component is present
    Access the Nagios XI web interface and navigate to Configure > Core Config Manager, or check for the /nagiosxi/ccm/ directory in the web root
    Affected if The CCM interface is accessible and present in the installation
  3. Check CCM overlay modal functionality
    Log into Nagios XI as an admin, open the Core Config Manager, and attempt to open any overlay modal (for example, clicking on a host or service configuration to trigger a modal). Inspect if the modal renders user-supplied data without encoding.
    Affected if The overlay modal displays unsanitized input when editing configuration objects that contain special characters in their names or descriptions

You are affected if Nagios XI is installed with a version earlier than 5.8.2 and the Core Config Manager component is accessible and in use.

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 5.8.2 or later
Fixed in 5.8.2
Interim mitigation

Upgrade to Nagios XI CCM 3.1.1 / XI 5.8.2 or later, which includes proper input validation and output encoding fixes for the affected overlay modals.

Recommended fix High confidence

Nagios XI 5.8.2 (which includes CCM 3.1.1)

  1. Verify current Nagios XI version by checking the admin interface or running: cat /usr/local/nagiosxi/var/version.txt
  2. Review the Nagios XI upgrade documentation at docs.nagios.com for pre-upgrade requirements
  3. Ensure backups are created of the Nagios XI database and configuration files
  4. Schedule maintenance window as upgrade may temporarily interrupt monitoring services
  5. Download Nagios XI 5.8.2 or later from the Nagios website (account may be required)
  6. Run the official Nagios XI upgrade script following documented procedures
  7. After upgrade, verify CCM version shows 3.1.1 or later
  8. Test Core Config Manager functionality to confirm overlay modals work correctly
Caveat Standard upgrade risks apply - ensure backups before proceeding; some configuration changes between major versions may require manual migration

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

Fix this in Nagios Xi Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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-2021-47690 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
  • No spam, self-promotion, credentials, or personal data