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Nagios XiApplication · Nagios

CVE-2026-2043

HIGH · 8.8 CVSS v3.1 Published 2026-02-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
94/100
Remediation priority · Urgent
High EPSS Remotely reachable Zero-click

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 Host esensors_websensor_configwizard_func Command Injection Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Nagios Host. Authentication is required to exploit this vulnerability. The specific flaw exists within the esensors_websensor_configwizard_func method. The issue results from the lack of proper validation of a user-supplied string before using it to execute a system call. An attacker can leverage this vulnerability to execute code in the context of the service account. Was ZDI-CAN-28249.

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 · high confidence

This is a command injection vulnerability in Nagios Host's esensors_websensor_configwizard_func method. The flaw results from insufficient validation of user-supplied input before using it in a system call, allowing an authenticated attacker to inject and execute arbitrary commands in the context of the service account.

MitigationImplement strict input validation and sanitization on all user-supplied parameters in the esensors_websensor_configwizard_func method, and consider employing parameterized system call APIs or whitelisting allowed characters to prevent command 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:= 2026

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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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. Verify Nagios XI installation and version
    Check the installed Nagios XI version using the system's package manager or Nagios-specific command (such as 'cat /usr/local/nagiosxi/etc/xi-version.txt' or checking RPM/DEB package version)
    Affected if The installed version is exactly 2026
  2. Confirm esensors_websensor_configwizard_func module exists
    Locate and examine the esensors_websensor_configwizard_func file or module within the Nagios XI installation directory structure, typically under the wizards or handlers directory
    Affected if The esensors_websensor_configwizard_func method file is present in the Nagios installation
  3. Verify the websensor config wizard is accessible
    Check if the esensors web sensor configuration wizard is enabled and accessible via the Nagios XI web interface by examining the configuration files that register available configuration wizards
    Affected if The esensors_websensor_configwizard_func wizard is listed as an active/available wizard in the Nagios configuration
  4. Check authentication mechanism status
    Review the Nagios XI authentication settings and user account configurations to confirm user authentication is active for accessing the configuration wizards
    Affected if User authentication is enabled and valid user credentials can be used to access the affected wizard functionality

If running Nagios XI version 2026 with the esensors_websensor_configwizard_func module enabled and accessible to authenticated users, the environment is affected by this command injection vulnerability.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement strict input validation and sanitization on all user-supplied parameters in the esensors_websensor_configwizard_func method, and consider employing parameterized system call APIs or whitelisting allowed characters to prevent command injection.

Fix this in Nagios Xi Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
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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-2026-2043 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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