What’s Vulnerable › Vulnerabilities
CVE-2026-84963: Silent field truncation via unchecked int cast of huge JSON string values in JSON-to-BSON parser
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-09-03 · updated 2026-09-22
- Weakness: CWE-681
Description
An incorrect numeric conversion in the JSON parsing component of the MongoDB C Driver's BSON library may cause an unusually large text value to be silently shortened, or the corresponding field to be omitted, while the parsing operation still reports success and returns no error. An unauthenticated party who can supply the input processed by an application that uses this component may cause that application to hold data that does not match what was submitted, which may result in unintended alteration of data.
Affected products
- MongoDB C# Driver: from 1.10.0 before 1.30.9; from 2.0.0 before 2.5.2 — fixed in 1.30.9, 2.5.2
How to fix
Upgrade to a fixed version: MongoDB C# Driver 1.30.9, 2.5.2. Check the vendor advisory for mitigations.
References
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