HIGH

CVE-2026-96749

Heap out-of-bounds write via signed size overflow in BSON document encoding

CVSS v3

8.4

HIGH

EPSS Score

0.1 %

exploit probability, as of 2026-09-28

CISA KEV

known exploited

Exploitation

none

SSVC status

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, dependin

Technical details

CVSS v3 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2026-09-24
Last Modified: 2026-09-26

Frequently asked questions

What is CVE-2026-96749?

Is CVE-2026-96749 actively exploited?

Active exploitation of CVE-2026-96749 has not been confirmed. Its EPSS score was 0.1% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-96749?

CVE-2026-96749 has a CVSS v3 base score of 8.4 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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