CVE-2026-40976: spring spring boot Missing Authorization

Vulnerability summary

CVE-2026-40976 is a critical (CVSS 9.1) Missing Authorization vulnerability in spring spring boot. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.1% of scored vulnerabilities.

Timeline

1. 27-04-2026
   PublishedVulnerability first disclosed.
2. 15-07-2026
   Last modifiedVulnerability information updated.

Description

In certain circumstances, Spring Boot's default web security is ineffective allowing unauthorized access to all endpoints. For an application to be vulnerable, it must: be a servlet-based web application; have no Spring Security configuration of its own and rely on the default web security filter chain; depend on spring-boot-actuator-autoconfigure; not depend on spring-boot-health. If any of the above does not apply, the application is not vulnerable. Affected: Spring Boot 4.0.0–4.0.5; upgrade to 4.0.6 or later per vendor advisory.

• CWE-862Missing AuthorizationThe product does not perform an authorization check when an actor attempts to access a resource or perform an action.
• CWE-305Authentication Bypass by Primary WeaknessThe authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.