CVE-2026-40976: In certain circumstances, Spring Boot's default web security is ineffective allowing unauthorized access to al

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CRITICAL 9.1REMOTEUPGRADE

CVE-2026-40976 is a critical-severity flaw (CVSS 9.1) affecting spring boot. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 vulner

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 58%)
CISA exploited list	No
Weakness	CWE-862, CWE-305
Published	2026-04-28
Last modified	2026-07-24

Publisher (CNA): VMware · Vendor: vmware

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-28 00:16 UTCPublished CVE record published
2026-07-24 21:10 UTCUpdated Record last modified

vmware spring boot UPGRADE

Affected: >= 4.0.0 and < 4.0.6

Fixed in: 4.0.6

Safe to downgrade to: a release before 4.0.0

1. Check installed version

apt-cache policy spring-boot || rpm -q spring-boot || spring-boot --version

2. UPGRADE to 4.0.6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade spring-boot

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade spring-boot

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 4.0.0 (Debian / Ubuntu)

apt-cache madison spring-boot sudo apt install spring-boot=<VERSION_BEFORE_4.0.0> sudo apt-mark hold spring-boot

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list spring-boot sudo dnf downgrade spring-boot-<VERSION_BEFORE_4.0.0> sudo dnf versionlock add spring-boot

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-40976?

spring boot: upgrade to 4.0.6. Exact commands for each OS are on this page.

Is CVE-2026-40976 being exploited?

CVE-2026-40976 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-40976 affect?

CVE-2026-40976 affects spring boot. Severity is critical (CVSS 9.1). 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 configurati

How urgent is CVE-2026-40976?

Priority 47/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

Spring Framework vulnerabilities · VMware vulnerabilities

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References

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