# CVE-2026-82059: Improper Access Restriction of Internal Aggregation Expression in MongoDB Server Leads to Assertion Failure and Denial of Service

CVE-2026-82059 is fixed in MongoDB on 1 platform by MongoDB 8.3.11 (version 8.3.11), released September 9, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-82059
- Priority: Routine
- CVSS: 6.0
- EPSS: 0.0037
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 8, 2026
- Weakness: CWE-617: Reachable Assertion
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-82059

## Description

An internal aggregation expression in MongoDB Server was incorrectly registered as accessible to any authenticated user rather than being restricted to internal cluster operations. By crafting a malformed index specification within this expression, an authenticated user with read-only privileges could trigger an assertion failure in the index key generation code path. In certain build configurations, this assertion failure results in termination of the mongod process, causing a denial of service to all connected clients.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | MongoDB | 8.3.11 | [MongoDB 8.3.11](https://patchblox.com/security/data/fix/windows-app/mongodb.server-8.3.11.md) | Sep 9, 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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