CVE-2026-6231: MongoDB C Driver

High severity, CVSS 7.5. EPSS: 0.3% chance of exploitation in the next 30 days.

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

Affected products

• MongoDB C Driver: before 1.30.5 (fixed in 1.30.5); from 2.0.0, before 2.0.2 (fixed in 2.0.2)

Published 2026-04-13. Last modified 2026-06-17.