CVE-2020-36866
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 · uneditedNagios XI versions prior to 5.7.3 are vulnerable to cross-site scripting (XSS) via the Manage Users page of the Admin interface. 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 confidenceNagios XI versions prior to 5.7.3 contain a stored XSS vulnerability in the Admin interface's Manage Users page. User-supplied input (likely username fields) is not properly validated or escaped before being stored and rendered, allowing injection of malicious JavaScript that executes in victim administrators' browsers.
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< 5.7.2CVSS 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 checksWork through these to decide whether this CVE applies to you.
-
Determine Nagios XI versionLocate the installed Nagios XI version in the system (typically visible in the web UI footer or via the system info page) and compare it to the affected range (versions prior to 5.7.2)Affected if Installed version is lower than 5.7.2
-
Access the Admin interfaceLog into the Nagios XI web interface and navigate to the Admin sectionAffected if You have administrative access to the Nagios XI management portal
-
Navigate to Manage Users pageIn the Admin interface, locate and open the Manage Users or Users configuration pageAffected if The Manage Users page is accessible in the admin interface
-
Inspect usernames for injected scriptsExamine each username entry displayed on the Manage Users page. Look for usernames containing script tags, HTML elements, or JavaScript event handlers (such as <script>, <img onerror=, javascript:, or similar patterns)Affected if Any username entries contain raw script tags or JavaScript code that could execute in a browser
You are affected if your Nagios XI version is below 5.7.2 AND the Manage Users page contains usernames with unescaped script content visible in the browser
Generated from the published advisory. Verify against your own configuration.
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 · scoped5.7.2
Upgrade Nagios XI to version 5.7.3 or later to patch this XSS vulnerability. Alternatively, restrict admin access and monitor the Manage Users page for suspicious input.
Nagios Xi 5.7.3 or later
- 1. Back up the current Nagios Xi installation and database before proceeding with any updates
- 2. Download Nagios Xi version 5.7.3 or later from the official Nagios download page (www.nagios.com)
- 3. Follow the official Nagios Xi upgrade documentation to apply the update
- 4. After upgrading, verify the version number matches 5.7.3 or later
- 5. Log in to the Admin interface and navigate to the Manage Users page to confirm the vulnerability is remediated
- 6. Test that user input fields properly escape special characters to prevent XSS
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-36866 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-36866 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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