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MongoDBDatabase / datastore

CVE-2026-8336

MEDIUM · 6.5 CVSS v3.1 Published 2026-05-13
Fix available
A fix is available. Upgrade to 8.2.9 / 8.3.2 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

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 · unedited
After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map function in a certain way, an authenticated user can subsequently crash mongod when the server-side JavaScript engine (through $where, $function, mapreduce reduce stage, etc.) is used also in a specific way, resulting in a post-authentication denial-of-service. This issue impacts MongoDB Server v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.

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 confidence

An authenticated user can trigger a denial-of-service by first invoking the internal $_internalJsEmit function (not intended for direct access) or using mapreduce map function in a specific way, then subsequently using MongoDB's server-side JavaScript engine ($where, $function, mapreduce reduce stage) in a particular sequence, causing mongod to crash.

MitigationUpgrade MongoDB Server to v8.2.9 or v8.3.2 or later. Until patched, limit access to authenticated users and monitor for suspicious JavaScript operation sequences.

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
Affected:>= 8.2.0, < 8.2.9>= 8.3.0, < 8.3.2

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Check MongoDB server version
    Run db.version() in mongosh or use mongod --version to retrieve the installed version
    Affected if Version is >= 8.2.0 and < 8.2.9, OR >= 8.3.0 and < 8.3.2
  2. Verify if server-side JavaScript is in use
    Check for recent usage of $where, $function operators, or mapreduce commands by reviewing logs or monitoring current operations with db.currentOp()
    Affected if Server-side JavaScript features ($where, $function, mapreduce) have been invoked after triggering $_internalJsEmit or mapreduce map function
  3. Review authentication configuration
    Check if authentication is enabled and review user privileges using db.getUsers() or authSchemaVersion in system.version collection
    Affected if Authenticated users have access to run JavaScript operations and the vulnerability requires an authenticated user trigger
  4. Check for mongod crash logs
    Examine MongoDB log files for crash events or assertions related to JavaScript execution, particularly around $_internalJsEmit or mapreduce operations
    Affected if Logs show mongod crashes occurring after the specific sequence of JavaScript operations described

A system is affected if it runs a vulnerable MongoDB version (8.2.0-8.2.9 or 8.3.0-8.3.2), has server-side JavaScript features enabled, and an authenticated user can trigger the specific operation sequence that causes the crash.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 8.2.9 / 8.3.2 or later
Fixed in 8.2.98.3.2
Interim mitigation

Upgrade MongoDB Server to v8.2.9 or v8.3.2 or later. Until patched, limit access to authenticated users and monitor for suspicious JavaScript operation sequences.

Recommended fix High confidence

MongoDB Server 8.2.9 (for 8.2.x line) or 8.3.2 (for 8.3.x line)

  1. 1. Backup your MongoDB data and configuration files before making any changes
  2. 2. Stop the MongoDB Server process (mongod)
  3. 3. Upgrade MongoDB Server to version 8.2.9 or later if using the 8.2.x branch, or to version 8.3.2 or later if using the 8.3.x branch
  4. 4. Verify the upgrade was successful by checking the installed version with: mongod --version
  5. 5. Restart the MongoDB Server with the upgraded binary
Caveat Point releases typically have minimal breaking changes; review MongoDB 8.2.9 and 8.3.2 release notes for any compatibility notes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in MongoDB Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-8336 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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