An integer overflow in the BSON document encoding component of the MongoDB Python Driver's bundled native extension may occur when a single document is built from an unusually large amount of caller-supplied data. Size arithmetic is performed in a signed 32-bit type, and the guard meant to catch the overflow is written in a form whose behavior is not defined by the C language standard. A party with no privileges who can place a very large value into data that an application encodes may, depending on how the native extension was built, cause a write outside the bounds of an allocated buffer inside the application's own process.
History

Fri, 25 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-787
References
Metrics threat_severity

None

threat_severity

Important


Fri, 25 Sep 2026 08:15:00 +0000

Type Values Removed Values Added
First Time appeared Mongodb
Mongodb python Driver
Vendors & Products Mongodb
Mongodb python Driver

Thu, 24 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
References
Metrics ssvc

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


Thu, 24 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
Description An integer overflow in the BSON document encoding component of the MongoDB Python Driver's bundled native extension may occur when a single document is built from an unusually large amount of caller-supplied data. Size arithmetic is performed in a signed 32-bit type, and the guard meant to catch the overflow is written in a form whose behavior is not defined by the C language standard. A party with no privileges who can place a very large value into data that an application encodes may, depending on how the native extension was built, cause a write outside the bounds of an allocated buffer inside the application's own process.
Title Heap out-of-bounds write via signed size overflow in BSON document encoding
Weaknesses CWE-190
References
Metrics cvssV3_1

{'score': 8.4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 7.5, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: mongodb

Published: 2026-09-24T18:18:13.077Z

Updated: 2026-09-26T03:55:41.712Z

Reserved: 2026-09-23T15:45:51.412Z

Link: CVE-2026-96749

cve-icon Vulnrichment

Updated: 2026-09-24T18:36:57.237Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-24T19:17:20.963

Modified: 2026-09-26T04:17:52.260

Link: CVE-2026-96749

cve-icon Redhat

Severity : Important

Publid Date: 2026-09-24T18:18:13Z

Links: CVE-2026-96749 - Bugzilla