CVE-2026-21228
Published: 10 February 2026
Summary
CVE-2026-21228 is a high-severity Improper Certificate Validation (CWE-295) vulnerability in Microsoft Azure Local. Its CVSS base score is 8.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 49.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SC-17 (Public Key Infrastructure Certificates) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-21228 is an improper certificate validation vulnerability (CWE-295) affecting Azure Local. Published on 2026-02-10, it carries a CVSS v3.1 base score of 8.1 (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating high severity due to its potential for significant confidentiality, integrity, and availability impacts.
An unauthorized attacker can exploit this vulnerability over a network with no required privileges or user interaction, though it demands high attack complexity. Successful exploitation allows the attacker to execute arbitrary code on the affected system.
The Microsoft Security Response Center provides an update guide with details on mitigation and patches at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21228.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-7310
Vulnerability details
Improper certificate validation in Azure Local allows an unauthorized attacker to execute code over a network.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Improper certificate validation enables unauthenticated remote code execution on a network-accessible Azure Local service, directly mapping to exploitation of public-facing applications for initial access and arbitrary code execution.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
SC-17 requires verification of PKI certificate validity using defined processes, directly addressing the improper certificate validation in CVE-2026-21228 that enables network-based code execution.
SI-2 mandates identification, reporting, and correction of system flaws, including timely patching of the Azure Local certificate validation vulnerability as detailed in the MSRC update guide.
SC-13 requires implementation of cryptographic protections with proper management of keys and certificates, mitigating risks from flawed certificate validation during network communications.