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CVE-2026-84966

MediumCVSS 5.9 / 10
Published Sep 3, 2026·Last modified Sep 24, 2026
Affected Components(26)
mongodb/mongo-cxx-driver
r4.5.0
mongodb/mongo-cxx-driver
r3.0.3
mongodb/mongo-cxx-driver
r3.6.0-rc0
1 / 9
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.

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Risk Scores
Base Score
5.9

The vulnerability requires local access to the device to be exploited. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability.

Threat Intelligence
2.1

Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.

EPSS
0.14%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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