CVE-2026-84965

Heap write primitive via size round-up wrap during JSON parsing on 32-bit builds

Published Sep 3, 2026 CVSS 4.0 · 5.9 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:mongodb:c_driver:*:*:*:*:*:mongodb:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mongodb
Mongodb c Driver
Vendors & Products Mongodb
Mongodb c Driver
Type Values Removed Values Added
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.
Title Heap write primitive via size round-up wrap during JSON parsing on 32-bit builds
Weaknesses CWE-190
References
Metrics cvssV3_1

{'score': 5.1, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 5.9, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mongodb
Published
Updated
Sep 3, 2026, 3:44 PM
Reserved
Sep 2, 2026, 5:58 PM
Status
Analyzed
Published
Sep 3, 2026, 4:18 PM
Modified
Sep 22, 2026, 4:00 PM