MongoDBDatabase / datastore
CVE-2026-9743
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 · uneditedIn MongoDB Server 8.0, an aggregation stage can leave its _subPipeline field null during processing of certain pipelines. If a getMore is subsequently issued on the same cursor, the server may dereference this null sub-pipeline when reattaching to the operation context, accessing an invalid address and crashing the process. This issue allows an authenticated user who can run aggregation pipelines to cause a denial of service by issuing a specially crafted aggregation followed by getMore on affected versions.
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 confidenceIn MongoDB Server 8.0, a null pointer dereference exists in the aggregation pipeline processing. When certain aggregation pipelines are executed, the _subPipeline field can be left null. If a getMore is subsequently issued on the same cursor, the server attempts to dereference this null sub-pipeline when reattaching to the operation context, causing a process crash.
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
>= 8.0.0, < 8.0.24CVSS 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 mongo shell or 'mongod --version' from command lineAffected if Version is 8.0.0 through 8.0.23 (any version >= 8.0.0 and < 8.0.24)
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Verify aggregation pipeline usageReview application code and logs for use of db.collection.aggregate() that returns a cursorAffected if Aggregation pipelines that return cursors are in use
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Identify getMore operations on aggregation cursorsCheck application behavior or server logs for getMore calls on aggregation results (e.g., cursor iteration beyond initial batch)Affected if Application iterates through aggregation results using getMore beyond the first batch
Environment is affected if running MongoDB 8.0.0 through 8.0.23 and applications use aggregation pipelines that return cursors with getMore iteration.
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 · scoped8.0.24
Apply the vendor patch for MongoDB Server 8.0 when available. Limit aggregation pipeline execution to trusted, authenticated users until the patch can be applied, as this vulnerability requires authenticated access.
8.0.24
- 1. Back up all MongoDB data and configuration files before proceeding with any upgrade.
- 2. Ensure your current MongoDB deployment is healthy and stable before scheduling the upgrade.
- 3. Review MongoDB 8.0 upgrade documentation at https://www.mongodb.com/docs/manual/release-notes/8.0/ for any version-specific considerations.
- 4. For standalone instances: Stop the mongod service, then reinstall or upgrade MongoDB to version 8.0.24 or later.
- 5. For replica sets: Perform a rolling upgrade following MongoDB's recommended rolling upgrade procedure - upgrade secondary members first, then primary, one at a time.
- 6. After upgrade, verify the MongoDB service starts successfully and the server version is correct using db.version()
- 7. Test that aggregation pipelines and cursor operations (including getMore) function correctly.
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in MongoDB
Scoped from the published advisory
- Consultation4.0 h
- Implementation4.0 h
- Testing6.0 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 $4,448.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-9743 — 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-2026-9743 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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