In certain circumstances, Spring Boot's default web security is ineffective allowing unauthorized access to all endpoints. For an application to be vu...
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.
AI Analyst Comment
Remediation
Update Unknown Multiple Products to the latest version. Monitor for exploitation attempts and review access logs.
---METADATA---
VENDOR: Spring
PRODUCT: Boot
AFFECTED_VERSIONS: 4.0.0–4.0.5
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Description Summary:
A default web security misconfiguration in Spring Boot 4.0.0–4.0.5 allows unauthenticated access to all endpoints in specific servlet-based applications.
Executive Summary:
A critical security misconfiguration in Spring Boot 4.0.0–4.0.5 allows unauthenticated attackers to bypass security controls and access all application endpoints.
Vulnerability Details
CVE-ID: CVE-2026-40976
Affected Software: Spring Boot
Affected Versions: 4.0.0–4.0.5
Vulnerability: This is a security bypass vulnerability resulting from ineffective default web security. It affects servlet-based applications that lack custom Spring Security configurations and rely solely on default settings while using
spring-boot-actuator-autoconfigure.Business Impact
With a CVSS score of 9.1, this vulnerability poses a severe risk of unauthorized access to sensitive application data and management endpoints. It can lead to complete exposure of backend services and potential data breaches, depending on the information exposed by the application's endpoints.
Remediation Plan
Immediate Action: Upgrade to Spring Boot version 4.0.6 or later immediately.
Proactive Monitoring: Review application access logs for unusual requests to sensitive endpoints and audit existing security configurations.
Compensating Controls: Implement custom Spring Security filters to explicitly secure all endpoints until the application can be updated.
Exploitation Status
Public Exploit Available: No
Analyst Notes: As of Apr 28, 2026, there is no public information indicating active exploitation. However, the nature of the flaw makes it a high-risk target for automated scanning.
Analyst Recommendation
Upgrade to the patched version of Spring Boot as soon as possible. Organizations should also review their application security posture to ensure that proper authentication and authorization controls are in place for all endpoints.