Is CVE-2026-40976 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-40976 being exploited in the wild.

How severe is CVE-2026-40976?

Critical severity, with a CVSS score of 9.1, published 28 April 2026.

Which products and versions are affected?

org.springframework.boot:spring-boot (Maven) ECOSYSTEM:introduced=4.0.0,fixed=4.0.6.

Is there a fix for CVE-2026-40976?

Yes. org.springframework.boot:spring-boot (Maven): upgrade to 4.0.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-40976 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-40976?

Check whether you run org.springframework.boot:spring-boot (Maven) or VMware Spring Boot at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-40976: Spring Boot authentication bypass in default web security filter chain

CVE-2026-40976 · Severity: critical · CVSS 9.1 · Published 2026-04-28

A vulnerability in Spring Boot, a widely used framework for building Java applications, can cause default security protections to fail. In specific configurations, this allows unauthorized users to access all parts of the application without a password. This could lead to the exposure of sensitive data or unauthorized changes to the system.

Technologies: org.springframework.boot:spring-boot (Maven), VMware Spring Boot. Vendors: Maven, VMware.

Quick answers

Is CVE-2026-40976 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-40976 being exploited in the wild.
How severe is CVE-2026-40976?: Critical severity, with a CVSS score of 9.1, published 28 April 2026.
Which products and versions are affected?: org.springframework.boot:spring-boot (Maven) ECOSYSTEM:introduced=4.0.0,fixed=4.0.6.
Is there a fix for CVE-2026-40976?: Yes. org.springframework.boot:spring-boot (Maven): upgrade to 4.0.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-40976 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-40976?: Check whether you run org.springframework.boot:spring-boot (Maven) or VMware Spring Boot at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

org.springframework.boot:spring-boot (Maven): upgrade to 4.0.6 or later

# set org.springframework.boot:spring-boot to 4.0.6 in your pom.xml or build.gradle

Technical details

An authentication bypass vulnerability exists in Spring Boot when using default web security configurations. The issue occurs in servlet-based web applications that rely solely on the default Spring Security filter chain, include the 'spring-boot-actuator-autoconfigure' dependency, and lack the 'spring-boot-health' dependency. Under these conditions, the default security constraints are not correctly applied, granting unauthenticated network attackers full access to all application endpoints. The vulnerability is addressed in Spring Boot version 4.0.6.

Affected products

Spring Spring Boot 4.0.0–4.0.5
Red Hat Red Hat Data Grid 8 8

Identifiers

CVE-2026-40976
GHSA-8v8j-3hxp-93wr

Timeline

2026-04-28: disclosed
2026-04-28: advisory

References

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