CVE-2026-40411
Published: 22 May 2026
Summary
CVE-2026-40411 is a critical-severity Improper Input Validation (CWE-20) vulnerability in Microsoft Azure Virtual Network Gateway. Its CVSS base score is 9.9 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 28.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Deeper analysisAI
Automated synthesis unavailable for this CVE.
Vulnerability
Improper input validation in Azure Virtual Network Gateway allows an authorized attacker to execute code over a network.
- CWE(s)
- OWASP Top 10 Web 2025
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-31510
Regulatory context (EU CRA / NIS2 / DORA / UK NIS Regulations)
EU Cyber Resilience Act — coordinated disclosure
Critical and high-severity vulnerabilities in products with digital elements may trigger coordinated-disclosure obligations under the EU Cyber Resilience Act (CRA, Regulation 2024/2847). Manufacturers placing products on the EU market must notify ENISA and the relevant CSIRTs without undue delay once active exploitation is known.
Affected Products
Threat picture
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct RCE via improper input validation on a network-accessible Azure service (public-facing gateway component).
Defense & controls
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.
Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.
Directly implements checks on information inputs to reject invalid data before processing.
Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.