MongoDBDatabase / datastore
CVE-2018-20805
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 · uneditedA user authorized to perform database queries may trigger denial of service by issuing specially crafted queries, which perform an $elemMatch . This issue affects MongoDB Server v4.0 versions prior to 4.0.5 and MongoDB Server v3.6 versions prior to 3.6.10.
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 confidenceMongoDB Server contains a denial-of-service vulnerability where authenticated users with database query permissions can trigger excessive resource consumption by issuing specially crafted queries using the $elemMatch operator. This affects unpatched versions v3.6 prior to 3.6.10 and v4.0 prior to 4.0.5.
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
MongoDBDatabase / datastore
>= 3.6.0, < 3.6.10>= 4.0.0, < 4.0.5CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Determine installed MongoDB versionRun 'db.version()' in mongosh/mongo shell, or execute 'mongod --version' from command lineAffected if Version is 3.6.0 through 3.6.9, or 4.0.0 through 4.0.4 (meaning less than 3.6.10 or less than 4.0.5)
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Verify if MongoDB authentication is enabledCheck the mongod configuration file (typically /etc/mongod.conf or /etc/mongodb.conf) for 'security.authorization' set to 'enabled', or 'security.keyFile' option; alternatively, try connecting without credentials to see if access is grantedAffected if Authentication is disabled - the vulnerability requires an authenticated user to exploit; if disabled, this specific CVE does not apply regardless of version
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Confirm presence of users with query permissionsRun 'db.getUsers()' or 'db.getRole()' commands to review user roles; look for any user assigned 'read', 'readWrite', or 'dbAdmin' roles on any databaseAffected if Authenticated users with query permissions exist in the system - these are the users who could trigger the DoS condition using $elemMatch queries
You are affected if your MongoDB version is between 3.6.0 and 3.6.9 or between 4.0.0 and 4.0.4, AND authentication is enabled, AND there are users with database query permissions present.
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 data3.6.104.0.5
Upgrade MongoDB Server to version 3.6.10 or later for the 3.6 branch, or 4.0.5 or later for the 4.0 branch, to resolve this vulnerability.
Fix this in MongoDB
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,656.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-20805 — 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-2018-20805 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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