# CVE-2026-106431: mongo-c-driver: An off-by-one error in the BSON bulk document writer in the MongoDB C Driver can write one zero byte immediately past...

CVE-2026-106431 is fixed in mongo-c-driver on 1 platform by DEBIAN-CVE-2026-106431 (version 2.5.6-1), released October 16, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-106431
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0010
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 8, 2026

## Description

An off-by-one error in the BSON bulk document writer in the MongoDB C Driver can write one zero byte immediately past a heap allocation when a document ends at a specific buffer boundary. An actor who can influence the size of documents serialized by an embedding application can corrupt adjacent process memory or terminate the process. Reaching this issue requires the application to use the BSON bulk-writer API and produce a precise cumulative document size.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | mongo-c-driver Debian 14 | 2.5.6-1 | [DEBIAN-CVE-2026-106431](https://patchblox.com/security/data/fix/linux/debian-cve-2026-106431.md) | Oct 16, 2026 |

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Data as of 2026-11-10T01:44:33Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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