What’s Vulnerable › Vulnerabilities
CVE-2026-84965: Heap write primitive via size round-up wrap during JSON parsing on 32-bit builds
- Severity: medium (CVSS 5.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.1% 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-190
Description
An integer wraparound in an allocation size calculation in the BSON library's JSON parsing code can cause a buffer to be released while a following copy operation still writes through the stale pointer. On builds where sizes are 32 bits, an unauthenticated party able to supply a sufficiently large JSON input to an application that links the library may cause that application to terminate unexpectedly, resulting in denial of service.
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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