Azure Web Apps EUVD-2026-18560

No special conditions — remote unauthenticated exploitation against default installations of Azure MCP Server. Attacker requires only network access to the vulnerable server; no authentication, user interaction, or special configuration required.

This vulnerability presents critical real-world risk despite lack of confirmed active exploitation. The CVSS 9.1 score accurately reflects severity given the attack characteristics: network-accessible (AV:N), low complexity (AC:L), no authentication required (PR:N), and no user interaction needed (UI:N). Attackers can trivially exploit this by sending unauthenticated requests to vulnerable endpoints. The authentication bypass nature (CWE-306) makes exploitation highly automatable, as attackers need only identify exposed Azure MCP Server instances and craft standard network requests. While no EPSS score or KEV listing is provided in available data, the combination of Microsoft cloud infrastructure targeting, critical CVSS rating, and straightforward exploitation path suggests this will attract rapid attacker attention. Organizations using Azure MCP Server should treat this as emergency-priority given the potential for mass scanning and automated exploitation once details become public. The confidentiality and integrity impacts indicate potential for data exfiltration and unauthorized configuration changes in cloud environments.

An external attacker identifies an Azure MCP Server instance exposed to the internet through port scanning or cloud asset enumeration. Without requiring any credentials, the attacker crafts standard HTTP or API requests targeting critical management functions that lack authentication checks. The server processes these unauthenticated requests, allowing the attacker to enumerate cloud configurations, extract sensitive customer data, API keys, or credentials stored within the management plane, and potentially modify configuration settings to establish persistence or expand access to connected Azure resources. The low complexity and lack of authentication requirements enable automated mass exploitation across multiple organizations.