CVE-2026-84966
BSON element injection via NUL-embedded document keys in builder append
CVSS Score
5.1
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-681 |
| Vendor | mongodb |
| Product | c++ driver |
| Ecosystems | |
| Industries | Technology |
| Published | Sep 3, 2026 |
| Last Updated | Sep 3, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Local
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
MongoDB / C++ Driver
3.2.0 < 4.5.2