CVE-2026-84966
Medium
Description
An incorrect numeric type conversion in the BSON document building component of the MongoDB C++ Driver may cause a length value to be interpreted incorrectly. When an application supplies an extremely large, non-terminated field name to the builder, the library may read memory outside the intended buffer and terminate the calling process. No authentication is required, but the calling application must pass the oversized name in a specific form.
SeverityMedium
CVSS5.1
Exploit probability—
Product
Mongodb C\+\+ Driver
PublishedSep 3, 2026
First seenSep 3, 2026
Weakness typeCWE-681CWE-681
How to fix
Update
- mongodb c\+\+_driver4.5.2 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mongodb c\+\+_driver | 3.0.0 ≤ v < 4.5.2 | 4.5.2 |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
In the Intelligence 360 plan
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.