CVE-2026-84966 — MEDIUM (5.1)

Vulnerability 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.

CVSS Score

5.1

MEDIUM

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

Related Weaknesses (CWE)

CWE-681

References

https://jira.mongodb.org/browse/CXX-3548

FAQ

What is CVE-2026-84966?

CVE-2026-84966 is a vulnerability with a CVSS score of 5.1 (MEDIUM). 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...

How severe is CVE-2026-84966?

CVE-2026-84966 has been rated MEDIUM with a CVSS base score of 5.1/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-84966?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.