MongoDBGHSA-h2g7-2gxh-c5v2
Heap write primitive via size round-up wrap during JSON parsing on 32-bit builds
Medium5.9CVE-2026-84965 · Published Sep 3, 2026
### Impact 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. ### Patches Fixed in 1.30.9 and 2.5.1. ### Workarounds Check length of input JSON prior to parsing. ### References https://jira.mongodb.org/browse/CDRIVER-6405
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| MongoDB C Driver Product | >= 1.10.0, < 1.30.9 | 1.30.9 |
| >= 2.0.0, < 2.5.2 | 2.5.2 |
Details and references
- CVSS 4.0
- CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Severity from
- GitHub (reviewed advisory)
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