Mongodb C\+\+ Driver
CVE-2026-84970
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.
What this means for your business
- It affects Mongodb C\+\+ Driver. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it only with access to the machine itself, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a less than 0.1% chance of attack attempts being seen in the next 30 days, ranking above 0% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Mongodb C\+\+ Driver, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Fastnexa security experts
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Scoring
- CVSS
- 6.2 (v3.1)
- Vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H- CVSS v4
- 5.9
- Weakness
- CWE-681
- Assigned by
- cna@mongodb.com
Dates
- Published
- 2026-09-03
- Last modified
- 2026-09-10
- Sources
- NVD
Affected products
- Mongodb C\+\+ Driver3.2.0 - 4.5.2
As listed in the NVD configuration data. Not a statement about your estate.