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Fencer Intel
medium 5.1

CVE-2026-106435 json

Application denial of service via out-of-bounds read in BSON Regex decoding in MongoDB Python Driver

published last mo. modified 13d ago also GHSA-98qm-wvgf-w4cf , EUVD-2026-95254

cvss
5.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 0%
public exploits
0
none known

Summary

The MongoDB Python Driver's binary accelerator can read outside a buffer when an application decodes malformed BSON containing a truncated regular-expression element without a trailing NUL byte. An actor who can supply BSON to the documented decode or decode_all API can cause the application process to terminate when the C extension is loaded. The driver's normal database wire-protocol path does not reach this code.

Patch / fix

  • pypi pymongo 4.18.3
  • mongodb python_driver 4.18.3
  • pymongo Debian 14 4.19.0-1

debian advisories DEBIAN-CVE-2026-106435

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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-2026-106435 updated cvss 5.1

pymongo: pymongo: Denial of Service via out-of-bounds read during malformed BSON decoding

  • Red Hat OpenShift AI (RHOAI) rhoai/odh-ogx-core-rhel9, rhoai/odh-llama-stack-core-rhel9, rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9, rhoai/odh-pipeline-runtime-pytorch-rocm-py312-rhel9, rhoai/odh-workbench-jupyter-pytorch-cuda-py312-rhel9, rhoai/odh-workbench-jupyter-pytorch-rocm-py312-rhel9, +9 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenStack Platform 13 (Queens) python-bson, python-pymongo-gridfs, python-pymongo 3.0.3-2.el7ost Red Hat OpenStack Platform 16.2 rhosp-rhel8/openstack-horizon, rhosp-rhel8/openstack-zaqar-wsgi Red Hat OpenStack Platform 17.1 python3-bson, python3-pymongo, rhosp-rhel9/openstack-horizon
    affected: workaround, no fix planned “Out of support scope”

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
partial
Assessed
last mo.

Exploit prediction

0.09% chance of exploitation in the next 30 days, higher than 0% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 5.9 CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 3.1 5.1 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 5.9 CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/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
NVD 3.1 4.7 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi pymongo
>=3.9.0, <4.18.3
4.18.3

Affected products

  • MongoDB Python Driver

Classification

Weakness

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.