# CVE-2026-8336: Post-authentication use-after-free error in $_internalJsEmit and mapreduce commands

CVE-2026-8336 is fixed in MongoDB on 1 platform by MongoDB 8.3.2 (version 8.3.2), released May 12, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-8336
- Priority: High
- CVSS: 7.7
- EPSS: 0.0026
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 13, 2026
- Weakness: CWE-416: Use After Free
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-8336

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | MongoDB | 8.3.2 | [MongoDB 8.3.2](https://patchblox.com/security/data/fix/windows-app/mongodb.server-8.3.2.md) | May 12, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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