CVE-2021-37351
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 before version 5.8.5 is vulnerable to insecure permissions and allows unauthenticated users to access guarded pages through a crafted HTTP request to the server.
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 confidenceNagios XI versions prior to 5.8.5 contain an insecure permissions vulnerability that allows unauthenticated attackers to bypass authentication controls and access protected pages via crafted HTTP requests. This authorization bypass stems from improper validation of session or permission states when handling specific HTTP endpoints.
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< 5.8.5CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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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Determine installed Nagios XI versionAccess the Nagios XI administration interface and navigate to the 'About' or 'System Information' page to view the installed version. Alternatively, use system package management commands (such as 'rpm -qa | grep nagiosxi' or 'dpkg -l | grep nagiosxi') to query the installed package version.Affected if The reported version number is lower than 5.8.5 (for example, 5.8.4, 5.8.3, 5.7.x, etc.)
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Verify version via command lineIf you have shell access to the Nagios XI server, check the version file typically located in the installation directory or use the 'nagiosxi' command line utility if available (for example, '/usr/local/nagiosxi/etc/version.ini' or similar version configuration files).Affected if The version file shows a release prior to 5.8.5
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Check Nagios XI component versionsQuery the Nagios XI database or administrative panels for individual component versions, as some installations may have mixed version states. Look for the core Nagios XI version string in the database or configuration files.Affected if Any core Nagios XI component reports version < 5.8.5
If the installed Nagios XI version is anything below 5.8.5, the environment is affected by this authentication bypass vulnerability and should be considered at risk from unauthenticated access attempts.
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 data5.8.5
Upgrade Nagios XI to version 5.8.5 or later to obtain the patched version. If immediate upgrade is not feasible, restrict network access to the Nagios XI management interface via firewall rules or VPN to limit exposure to unauthenticated attackers.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-37351 — 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-2021-37351 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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- Version or environment caveats, and links to real fixes
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