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Fencer Vulns
medium 6.5

CVE-2026-96748 json

Connection redirection via percent-encoded delimiter injection in connection string hosts

published 2026-09-24 45 d ago modified 2026-10-15 25 d ago also GHSA-vp6j-j7w5-5xjj , PYSEC-2026-4297 , EUVD-2026-86347

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

PyMongo's connection string parsing decodes percent-encoded characters in the host portion before the host list is separated on its delimiters. When an application places a hostname value supplied by an unauthenticated party into a connection string, that party may cause additional servers of their choosing to be added to the application's database client. The application may then send its authentication exchange and database operations to one of those servers, which can observe limited information and return altered results.

Patch / fix

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

debian advisories DEBIAN-CVE-2026-96748

  • 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-2026-96748 updated cvss 6.5

pymongo: pymongo: Database connection redirection via percent-encoded host delimiter injection

  • 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
45 d ago

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
CNA 4.0 8.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/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 6.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
GitHub 3.1 6.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N

Affected packages

ecosystem package affected fixed in
pypi pymongo
>=3.5.0, <4.18.2
4.18.2

Affected products

  • MongoDB Python Driver

Classification

Weakness
  • CWE-177 Improper Handling of URL Encoding (Hex Encoding)

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.