MongoDBDatabase / datastore
CVE-2020-7926
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 cause denial of service by issuing a specially crafted query which violates an invariant in the server selection subsystem. This issue affects MongoDB Server v4.4 versions prior to 4.4.1. Versions before 4.4 are not affected.
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 confidenceA specially crafted database query from an authorized user can trigger a denial of service by violating an invariant in MongoDB's server selection subsystem. The vulnerability exists in the code path that selects replica set members or shards for query routing, where the malformed query causes an internal consistency check to fail.
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
>= 4.4.0, < 4.4.1CVSS 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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Check MongoDB server versionRun 'db.version()' in the mongo shell or execute 'mongod --version' from command lineAffected if The version is >= 4.4.0 and < 4.4.1
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Verify replica set or sharded cluster configurationRun 'rs.status()' or 'sh.status()' in the mongo shell to check if the deployment uses replica sets or shardingAffected if The database is configured as a replica set or sharded cluster (the vulnerability exists in these selection paths)
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Confirm authentication is enabledRun 'db.adminCommand({getCmdLineOpts: 1})' and check for 'authorization' setting, or check if the auth parameter is enabled in the configuration fileAffected if Authentication is enabled (the attack requires an authorized user, so both the vulnerability AND authenticated access must exist)
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Check for server selection crash logsInspect MongoDB log files for assertion failures, crashes, or errors containing 'server selection' or 'invariant' violations occurring around the time of suspicious queriesAffected if Logs show server selection subsystem crashes or invariant check failures
You are affected if your MongoDB version is between 4.4.0 and 4.4.1 (exclusive), you are running a replica set or sharded cluster, and authenticated users can execute queries.
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 data4.4.1
Upgrade MongoDB Server to version 4.4.1 or later. Ensure database access is restricted to authorized users only, as this DoS requires authenticated query access.
Fix this in MongoDB
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 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 $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-7926 — 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-2020-7926 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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