CVE-2026-40976 Spring Boot's default security filter chain has no authorization rule with Actuator but without Health
Attackers can access all endpoints in specific Spring Boot configurations lacking custom security, leading to unauthorized data exposure or modification.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40976?
CVE-2026-40976 is a critical missing authorization vulnerability in Spring Boot, published on 27 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-40976?
2 open source packages ship an affected version, including org.springframework.boot:spring-boot. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.springframework.boot:spring-boot Maven | From 4.0.0 | 4.0.6 |
org.springframework.boot:spring-boot Maven | From 4.0.0 | 4.0.6 |
Products include Vmware Spring Boot.
How do I fix CVE-2026-40976?
Upgrade org.springframework.boot:spring-boot to 4.0.6 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-40976 being exploited?
There is no known exploitation of CVE-2026-40976 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Spring Boot
- CVE-2023-20873 Spring Boot Security Bypass with Wildcard Pattern Matching on Cloud Foundry
- CVE-2026-22731 Authentication Bypass under Actuator Health groups paths
- CVE-2026-22733 Authentication Bypass under Actuator CloudFoundry endpoints
- CVE-2022-27772 Temporary Directory Hijacking to Local Privilege Escalation Vulnerability in org.springframework.boot:spring-boot
- CVE-2026-40972 Spring Boot DevTools remote secret comparison is vulnerable to timing attacks
Sources
Also known as CLEANSTART-2026-KC47770, CLEANSTART-2026-UJ95320, GHSA-8v8j-3hxp-93wr, MINI-235v-2h4r-f866, ROOT-APP-MAVEN-CVE-2026-40976.