# CVE-2026-11933: Post-authentication use-after-free in server-side JavaScript BSON-to-array conversion

CVE-2026-11933 is fixed in MongoDB on 1 platform by MongoDB 8.3.4 (version 8.3.4), released June 11, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-11933
- Priority: High
- CVSS: 8.7
- EPSS: 0.0038
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 12, 2026
- Weakness: CWE-787: Out-of-bounds Write
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-11933

## Description

A use-after-free vulnerability exists in MongoDB Server's server-side JavaScript engine when converting BSON documents to JavaScript arrays. An authenticated user with read privileges who is able to run server-side JavaScript (for example, via $where or $function) can cause the server to access memory that has already been freed. This may result in disclosure of information from the mongod process memory or a denial of service through a server crash.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | MongoDB | 8.3.4 | [MongoDB 8.3.4](https://patchblox.com/security/data/fix/windows-app/mongodb.server-8.3.4.md) | Jun 11, 2026 |

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Data as of 2026-11-08T13:06:02Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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