# CVE-2026-84969: mongo-c-driver: A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of by...

CVE-2026-84969 is fixed in mongo-c-driver on 1 platform by DEBIAN-CVE-2026-84969 (version 2.5.2-1), released September 10, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-84969
- Priority: Routine
- CVSS: 3.7 (low)
- EPSS: 0.0027
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 3, 2026

## Description

A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | mongo-c-driver Debian 14 | 2.5.2-1 | [DEBIAN-CVE-2026-84969](https://patchblox.com/security/data/fix/linux/debian-cve-2026-84969.md) | Sep 10, 2026 |

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Data as of 2026-11-09T07:25:28Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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