---
id: CVE-2026-21226
aliases:
  - GHSA-jm66-cg57-jjv5
  - PYSEC-2026-1208
title: Azure Core is vulnerable to deserialization of untrusted data
summary: Azure Core is vulnerable to deserialization of untrusted data
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
vendor: azure-core
product: azure-core
ecosystem: pip
affected:
  - azure-core < 1.38.0
patched:
  - azure-core 1.38.0
published: '2026-01-13'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:50:33.330380695Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-jm66-cg57-jjv5'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-21226'
  - url: 'https://github.com/Azure/azure-sdk-for-python'
  - url: >-
      https://github.com/Azure/azure-sdk-for-python/blob/6d2e6431ea0991861640e449e51e894247a7771a/sdk/core/azure-core/CHANGELOG.md#1380-2026-01-12
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21226'
tags:
  - osv
  - pip
epss: 0.00929
epssPercentile: 0.58993
ingestedAt: '2026-07-08T18:25:50.832Z'
---

## Overview

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

## Affected packages

- `azure-core < 1.38.0`

## Remediation

Upgrade to a patched release:

- `azure-core 1.38.0`