# CVE-2026-6231: mongo-c-driver: The bson_validate function may return early on specific inputs and incorrectly report success

CVE-2026-6231 is fixed in mongo-c-driver on 1 platform, first by DEBIAN-CVE-2026-6231, released April 13, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-6231
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0018
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 13, 2026

## Description

The bson_validate function may return early on specific inputs and incorrectly report success. This behavior could result in skipping validation for BSON data, allowing malformed or invalid UTF-8 sequences to bypass validation and be processed incorrectly. The issue may affect applications that rely on these functions to validate untrusted BSON data before further processing. This issue affects MongoDB C Driver versions prior to 1.30.5, MongoDB C Driver version 2.0.0 and MongoDB C Driver version 2.0.1

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | mongo-c-driver Debian 12.15 (bookworm) | 1.23.1-1+deb12u3 | [DEBIAN-CVE-2026-6231](https://patchblox.com/security/data/fix/linux/debian-cve-2026-6231.md) | Apr 13, 2026 |
| Linux | mongo-c-driver Debian 13.5 (trixie) | 1.30.4-1+deb13u2 | [DEBIAN-CVE-2026-6231](https://patchblox.com/security/data/fix/linux/debian-cve-2026-6231.md) | Apr 13, 2026 |
| Linux | mongo-c-driver Debian 14 | 2.1.0-1 | [DEBIAN-CVE-2026-6231](https://patchblox.com/security/data/fix/linux/debian-cve-2026-6231.md) | Apr 13, 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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