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Log ServerApplication · Nagios

CVE-2020-36858

MEDIUM · 5.4 CVSS v3.1 Published 2025-10-30
Fix available
A fix is available. Upgrade to 2.1.6 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 Log Server versions prior to 2.1.6 contain cross-site scripting (XSS) vulnerabilities via the web interface on the Create User, Edit User, and Manage Host Lists pages. 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 · high confidence

Nagios Log Server versions before 2.1.6 have stored XSS vulnerabilities in the Create User, Edit User, and Manage Host Lists pages of the web interface. Insufficient input validation allows attackers to inject malicious scripts that execute in victims' browsers.

MitigationUpgrade to Nagios Log Server 2.1.6 or later which contains the fix; additionally implement output encoding and input validation on affected pages as a defense-in-depth measure.

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
Log ServerApplication
Affected:< 2.1.6

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 if Nagios Log Server is installed
    Locate Nagios Log Server installation directory or check for running nagioslogserver service/process. Typical paths include /usr/local/nagios/logserver/ or /opt/nagios/logserver/. Use 'ps aux | grep nagios' or check system service status.
    Affected if Nagios Log Server is not installed or no matching process is found.
  2. Check installed version against vulnerable range
    Find the version file or use command line: navigate to the installation directory and look for a version file (often version.txt, about.php, or similar), or run 'nagioslogserver --version' if available. Compare the version number to 2.1.6.
    Affected if Installed version is earlier than 2.1.6 (e.g., 2.1.5, 2.1.0, 1.x.x).
  3. Verify web interface accessibility
    Confirm the Nagios Log Server web interface is accessible by attempting to reach the login page (typically on port 443 or 8080 via HTTP/HTTPS). The XSS vulnerabilities exist in the web interface pages.
    Affected if Web interface is accessible and running a version lower than 2.1.6.
  4. Confirm presence of vulnerable pages
    Access the web interface and navigate to: 1) Create User page, 2) Edit User page, 3) Manage Host Lists page. These are the three locations where the stored XSS vulnerabilities exist due to insufficient input validation.
    Affected if Any of these three pages are accessible and the installed version is below 2.1.6.

A user is affected if Nagios Log Server is installed with a version lower than 2.1.6 and the web interface with Create User, Edit User, or Manage Host Lists pages is accessible.

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 2.1.6 or later
Fixed in 2.1.6
Interim mitigation

Upgrade to Nagios Log Server 2.1.6 or later which contains the fix; additionally implement output encoding and input validation on affected pages as a defense-in-depth measure.

Recommended fix Moderate confidence

Nagios Log Server 2.1.6

  1. 1. Back up the current Nagios Log Server installation and all configuration data
  2. 2. Download Nagios Log Server version 2.1.6 from the official Nagios website (www.nagios.com)
  3. 3. Follow Nagios upgrade documentation to install version 2.1.6, replacing the existing installation
  4. 4. Verify the upgrade was successful by checking the version number in the web interface
  5. 5. Log in to the web interface and navigate to the Create User, Edit User, and Manage Host Lists pages to confirm the XSS vulnerability has been remediated

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

Fix this in Log Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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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-2020-36858 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