MongoDB C++ Driver up to 4.5.1 JSON Parsing numeric truncation error

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.3$0-$5k0.91

Summaryinfo

A vulnerability classified as very critical was found in MongoDB C++ Driver up to 4.5.1. Affected by this issue is some unknown functionality of the component JSON Parsing. The manipulation results in numeric truncation error. This vulnerability is cataloged as CVE-2026-84970. The attack must be initiated from a local position. There is no exploit available.

Detailsinfo

A vulnerability was found in MongoDB C++ Driver up to 4.5.1. It has been classified as very critical. Affected is an unknown function of the component JSON Parsing. The manipulation with an unknown input leads to a numeric truncation error vulnerability. CWE is classifying the issue as CWE-197. Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

A numeric truncation weakness exists in the JSON parsing component of the MongoDB C++ Driver's BSON library. An actor who controls the text that an embedding application hands to the library's public JSON parsing interface, when that text is very large, can cause the library to read memory beyond the supplied buffer and return it to the caller, to silently accept only part of the input as a complete document, or to terminate the process. No MongoDB server, credentials, or non-default configuration is required; the effect is confined to the process that uses the library.

The advisory is available at jira.mongodb.org. This vulnerability is traded as CVE-2026-84970 since 09/02/2026. The exploitability is told to be easy. Local access is required to approach this attack. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 09/03/2026).

Upgrading to version 4.5.2 eliminates this vulnerability.

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Productinfo

Type

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.3

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.2
CNA Vector (mongodb): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Numeric truncation error
CWE: CWE-197 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: C++ Driver 4.5.2

Timelineinfo

09/02/2026 CVE reserved
09/03/2026 +1 days Advisory disclosed
09/03/2026 +0 days VulDB entry created
09/03/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: jira.mongodb.org
Status: Confirmed

CVE: CVE-2026-84970 (🔒)
GCVE (CVE): GCVE-0-2026-84970
GCVE (VulDB): GCVE-100-398454

Entryinfo

Created: 09/03/2026 17:24
Changes: 09/03/2026 17:24 (76)
Complete: 🔍
Cache ID: 216::103

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