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Fencer Intel
high 8.4

CVE-2026-96749 json

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

published last mo. modified 27d ago also EUVD-2026-86348 , GHSA-v4x9-3549-crwv , PYSEC-2026-4296

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

Is CVE-2026-96749 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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
last mo.

Exploit prediction

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

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
GitHub 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

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 Intel 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.

The maintainers of mongodb/mongo-python-driver published their own advisory on GitHub. Reviewed sources take precedence over it.