🟠 High | Source: Microsoft Security Response Center
A vulnerability has been disclosed in NGINX’s ngx_http_ssi_module, tracked as CVE-2026-56434, with details published via the Microsoft Security Response Center in relation to Azure. The ngx_http_ssi_module handles Server Side Includes processing in NGINX, and flaws in this component can potentially allow attackers to manipulate web responses or cause unintended behaviour in hosted applications. This is relevant to Azure customers running NGINX-based workloads, including those using Azure Application Gateway, Azure Kubernetes Service, or self-managed NGINX deployments.
Security Architect’s Take: Identify any Azure-hosted or self-managed NGINX deployments using the ngx_http_ssi_module and assess whether SSI processing is enabled — if it is not required, disable the module to reduce attack surface. Monitor Microsoft’s MSRC advisory page for patch availability and prioritise patching NGINX instances exposed to untrusted input.
Original advisory: CVE-2026-56434 NGINX ngx_http_ssi_module vulnerability