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Fencer Vulns
high 8.4

CVE-2026-96749 json

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

published 2026-09-24 45 d ago modified 2026-10-15 25 d ago also GHSA-v4x9-3549-crwv , PYSEC-2026-4296 , EUVD-2026-86348

cvss
8.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi pymongo 4.18.2
  • MongoDB Python Driver 4.18.2
  • pymongo Debian 14 4.18.2-1

debian advisories DEBIAN-CVE-2026-96749

  • python-pymongo SLE Module for Package Hub 15 SP7 3.11.0-150300.3.6.1

suse advisories SUSE-SU-2026:4398-1

  • python-pymongo openSUSE Tumbleweed 4.18.2-1.1
  • python-pymongo openSUSE Leap 16.0 4.6.3-bp160.2.1

opensuse advisories openSUSE-SU-2026:11935-1openSUSE-SU-2026:22003-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-96749 updated cvss 6.2

pymongo: pymongo: Out-of-bounds write via integer overflow during BSON encoding

  • Red Hat Enterprise Linux 8 python2-bson, python3-bson, python-pymongo, python2-pymongo, python3-pymongo, python2-pymongo-gridfs, +1 more Red Hat OpenShift AI (RHOAI) rhoai/odh-ogx-core-rhel9, rhoai/odh-llama-stack-core-rhel9
    affected: no fix available
  • Red Hat OpenStack Platform 13 (Queens) python-bson, python-pymongo-gridfs, python-pymongo 3.0.3-2.el7ost
    affected: no fix planned “Will not fix”
  • Red Hat OpenStack Platform 17.1 python3-bson, python3-pymongo, rhosp-rhel9/openstack-horizon
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift AI 2.25 rhoai/odh-pipeline-runtime-pytorch-llmcompressor-cuda-py312-rhel9 1791867208
    fixed: vendor fix RHSA-2026:87410
  • Red Hat OpenShift AI 3.5 rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9 1791816462, rhoai/odh-pipeline-runtime-pytorch-rocm-py312-rhel9 1791951049, rhoai/odh-workbench-jupyter-pytorch-cuda-py312-rhel9 1791817064, rhoai/odh-workbench-jupyter-pytorch-rocm-py312-rhel9 1791816223, rhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9 1791816316, rhoai/odh-pipeline-runtime-datascience-cpu-py312-rhel9 1791952873, +7 more
    fixed: vendor fix RHSA-2026:86891
  • Red Hat OpenShift AI 2.25 rhoai/odh-rhel9-operator 1792570619, rhoai/odh-vllm-cpu-rhel9 1792018436, rhoai/odh-dashboard-rhel9 1791853525, rhoai/odh-modelmesh-rhel9 1790881700, rhoai/odh-operator-bundle 1792571069, rhoai/odh-vllm-cuda-rhel9 1791358976, +65 more Red Hat OpenShift AI 3.5 rhoai/odh-cli-rhel9 1791945905, rhoai/rhai-cli-rhel9 1791945905, rhoai/odh-automl-rhel9 1791916705, rhoai/odh-mlflow-rhel9 1791947857, rhoai/odh-autorag-rhel9 1791903266, rhoai/odh-trainer-rhel9 1791952138, +100 more
    not affected: vulnerable code not present
  • Red Hat OpenStack Platform 16.2 rhosp-rhel8/openstack-horizon, rhosp-rhel8/openstack-zaqar-wsgi
    not affected: vulnerable code not in execute path

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
45 d ago

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 7.5 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
CNA 3.1 8.4 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 4.0 7.5 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
OSV 3.1 8.4 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 8.4 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
pypi pymongo
<4.18.2
4.18.2

Affected products

  • MongoDB Python Driver

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.