- What: A deserialization vulnerability exists in the Azure Core shared client library for Python.
- Impact: A remote attacker can execute arbitrary code on the target system by passing specially crafted data.
- Affected: Azure Core shared client library for Python.
- Patch: Install the update from the vendor's website.
- CVE: CVE-2026-21226
Main Vulnerability Database SB2026020978 SB2026020978 - Fedora 42 update for python-azure-core Published: February 9, 2026 Security Bulletin ID SB2026020978 Severity Medium Patch available YES Number of vulnerabilities 1 Exploitation vector Remote access Highest impact Code execution Breakdown by Severity Low Medium High Critical Description This security bulletin contains information about 1 security vulnerability. 1) Deserialization of Untrusted Data (CVE-ID: CVE-2026-21226) The vulnerability allows a remote attacker to execute arbitrary code on the target system. The vulnerability exists due to insecure input validation when processing serialized data in Azure Core shared client library for Python. A remote user can pass specially crafted data to the application and execute arbitrary code on the target system. Successful exploitation of this vulnerability may result in complete compromise of vulnerable system. Remediation Install update from vendor's website. References https://bodhi.fedoraproject.org/updates/FEDORA-2026-3beebfc8ff