CVE-2021-26023
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 · uneditedThe Favorites component before 1.0.2 for Nagios XI 5.8.0 is vulnerable to XSS.
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 confidenceThe Favorites component in Nagios XI 5.8.0 before version 1.0.2 contains a Cross-Site Scripting (XSS) vulnerability. This allows an attacker to inject malicious scripts through the Favorites functionality that will execute in the context of other users' sessions when they view the affected pages.
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< 1.0.2CVSS 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
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/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.
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Locate the Nagios XI installationCheck for Nagios XI directories such as /usr/local/nagiosxi/ or /opt/nagiosxi/, or run 'rpm -qa | grep nagiosxi' on Linux systemsAffected if Nagios XI is not installed, this CVE does not apply
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Identify the Favorites component versionNavigate to the favorites component directory (typically /usr/local/nagiosxi/html/includes/components/favorites/) and look for a version file, changelog, or the main PHP file header that states the component versionAffected if The installed Favorites component version is less than 1.0.2 (e.g., 1.0.1, 1.0.0, or no version displayed)
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Verify the Favorites component is loadedCheck if the favorites component is enabled by reviewing the Nagios XI component configuration at /usr/local/nagiosxi/html/includes/components/ or by accessing the Nagios XI admin interface under Admin > System Extensions > Component StatusAffected if The Favorites component shows as active or enabled in the component list
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Confirm user access to Favorites functionalityLog into Nagios XI as a standard user and navigate to any page with a Favorites button/star icon, or check the database table 'xi_us favorites' if you have database accessAffected if The Favorites feature is accessible and users can add/manage favorites in their session
You are affected if Nagios XI is installed with a Favorites component version prior to 1.0.2 and the Favorites feature is enabled and accessible to users.
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.
From vendor data1.0.2
Update the Favorites component to version 1.0.2 or later, or upgrade Nagios XI to a version that includes the patched Favorites component.
- Consultation3.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,832.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-26023 — 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-2021-26023 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
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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