Spring - Spring Boot - CRITICAL - CVE-2026-40976. A security vulnerability exists in Spring Boot that could allow unauthorized access to all endpoints in certain servlet-based applications. This issue arises when applications rely on the default web security filter chain without custom security configurations. Specifically, applications dependent on spring-boot-actuator-autoconfigure, while not utilizing spring-boot-health, can be exploited. Users are advised to upgrade to Spring Boot version 4.0.6 or later to mitigate this risk.