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.
Published: 2026-09-03
Score: 5.9 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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References
History

Thu, 03 Sep 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 03 Sep 2026 16:45:00 +0000

Type Values Removed Values Added
First Time appeared Mongodb
Mongodb c++ Driver
Vendors & Products Mongodb
Mongodb c++ Driver

Thu, 03 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
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.
Title BSON element injection via NUL-embedded document keys in builder append
Weaknesses CWE-681
References
Metrics cvssV3_1

{'score': 5.1, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 5.9, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


Subscriptions

Mongodb C++ Driver
cve-icon MITRE

Status: PUBLISHED

Assigner: mongodb

Published:

Updated: 2026-09-03T15:38:58.400Z

Reserved: 2026-09-02T17:58:52.742Z

Link: CVE-2026-84966

cve-icon Vulnrichment

Updated: 2026-09-03T15:38:55.196Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-03T16:18:25.563

Modified: 2026-09-03T16:25:43.557

Link: CVE-2026-84966

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-03T16:45:06Z

Weaknesses
  • CWE-681

    Incorrect Conversion between Numeric Types