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Fencer Vulns
high 7.5

CVE-2026-21226 json

Azure Core shared client library for Python Remote Code Execution Vulnerability

published 2026-01-13 9 mo ago modified 2026-09-10 1 mo ago also GHSA-jm66-cg57-jjv5 , PYSEC-2026-1208 , EUVD-2026-2009

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

Deserialization of untrusted data in Azure Core shared client library for Python allows an authorized attacker to execute code over a network.

Patch / fix

  • pypi azure-core 1.38.0
  • Microsoft Azure Core shared client library for Python 1.38.0
  • azure-cli SLE Module for Public Cloud 15 SP7, SLE Module for Public Cloud 15 SP6, SLE Module for Public Cloud 15 SP5 +2 more 2.82.0-150400.14.23.1
  • python-h11 SLE Module for Python 3 15 SP7, SLE Module for Public Cloud 15 SP6, SLE Module for Public Cloud 15 SP5 +2 more 0.14.0-150400.9.8.1
  • python-msal SLE Module for Public Cloud 15 SP7, SLE Module for Public Cloud 15 SP6, SLE Module for Public Cloud 15 SP5 +2 more 1.35.0~b1-150400.11.11.2
  • python-trio SLE Module for Python 3 15 SP7, SLE Module for Public Cloud 15 SP6, SLE Module for Public Cloud 15 SP5 +2 more 0.30.0-150400.9.8.1
  • python-anyio SLE Module for Python 3 15 SP7, SLE Module for Public Cloud 15 SP6, SLE Module for Public Cloud 15 SP5 +2 more 4.1.0-150400.9.6.1
  • python-httpx SLE Module for Python 3 15 SP7, SLE Module for Public Cloud 15 SP6, SLE Module for Public Cloud 15 SP5 +2 more 0.24.0-150400.9.7.1
  • azure-cli-core SLE Module for Public Cloud 15 SP7, SLE Module for Public Cloud 15 SP6, SLE Module for Public Cloud 15 SP5 +2 more 2.82.0-150400.14.14.1
  • python-outcome SLE Module for Python 3 15 SP7, SLE Module for Public Cloud 15 SP6, SLE Module for Public Cloud 15 SP5 +2 more 1.2.0-150400.9.5.1

suse advisories SUSE-RU-2026:2237-1SUSE-SU-2026:20621-1SUSE-SU-2026:20617-1SUSE-SU-2026:0476-1

  • python-azure-core openSUSE Leap 16.0 1.32.0-160000.3.1
  • python-azure-core openSUSE Tumbleweed 1.38.0-2.1

opensuse advisories openSUSE-SU-2026:20292-1openSUSE-SU-2026:10161-1

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-2026-21226 updated cvss 7.5

azure-core: Azure Core shared client library for Python Remote Code Execution Vulnerability

  • Red Hat Confidential Compute Attestation openshift-sandboxed-containers/osc-podvm-builder-rhel9 Red Hat Fence Agents Remediation Operator workload-availability/fence-agents-remediation-rhel9-operator Red Hat Migration Toolkit for Containers rhmtc/openshift-migration-hook-runner-rhel8
    affected: workaround, no fix available
  • Red Hat Ansible Automation Platform 2 python-azure-core 1.19.1-2.el8pc, python3.11-azure-core 1.34.0-1.el9ap, python3.12-azure-core 1.34.0-2.el8ap, ansible-automation-platform-24/controller-rhel8, ansible-automation-platform-25/controller-rhel8, ansible-automation-platform-26/controller-rhel9, +11 more
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-kserve-storage-initializer-rhel9 Red Hat Quay 3 quay/quay-rhel8, quay/quay-rhel9
    affected: workaround, no fix available
  • Red Hat Lightspeed Core lightspeed-core/lightspeed-stack-rhel9 Red Hat Migration Toolkit for Applications 8 mta/mta-solution-server-rhel9 Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-service-api-rhel9, openshift-lightspeed/lightspeed-agentic-sandbox-rhel9 Red Hat AI Inference Server rhaii/vllm-rocm-rhel9, rhaii-fast/vllm-rocm-rhel9 Red Hat Ansible Automation Platform 2 automation-controller 4.5.37-1.el8ap, ansible-automation-platform-26/hub-rhel9, ansible-automation-platform-27/hub-rhel9, ansible-automation-platform-25/de-minimal-rhel8, ansible-automation-platform-25/de-minimal-rhel9, ansible-automation-platform-26/de-minimal-rhel9, +7 more Red Hat Enterprise Linux 8 fence-agents, fence-agents-all, fence-agents-apc, fence-agents-aws, fence-agents-eps, fence-agents-gce, +43 more
    +4 more products
    Red Hat Enterprise Linux 9 fence-virt, fence-virtd, fence-agents, fence-virtd-cpg, fence-virtd-tcp, fence-agents-all, +51 more Red Hat Enterprise Linux 10 fence-agents-common Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-rocm-rhel9, rhelai3/bootc-azure-rocm-rhel9 Red Hat OpenShift AI (RHOAI) rhoai/odh-kserve-agent-rhel9, rhoai/odh-kserve-router-rhel9, rhoai/odh-feature-server-rhel9, rhoai/odh-kserve-controller-rhel9, rhoai/odh-kserve-autogluon-server-rhel9
    not affected: vulnerable code not present

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
9 mo ago

Exploit prediction

0.95% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
pypi azure-core
<1.38.0
1.38.0

Affected products

  • Microsoft Azure Core shared client library for Python

Classification

Weakness
  • CWE-502 Deserialization of Untrusted Data

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.