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CVE-2026-40976 — spring-boot

CRITICAL

CVE-2026-40976 is a critical-severity (CVSS 9.1) CWE-862 vulnerability in org.springframework.boot:spring-boot. A fix is available for org.springframework.boot:spring-boot — see the affected versions and patch details below.

Spring Boot's default security filter chain has no authorization rule with Actuator but without Health

Also known asGHSA-8v8j-3hxp-93wr
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40976.

EPSS Exploitation Probability

via FIRST.org ↗
0.5%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs42th percentile — riskier than 42% of all scored CVEsHighest risk
0.00%0.35%0.69%1.04%0.0%0.5%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
☕org.springframework.boot:spring-boot

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.springframework.boot:spring-boot≥ 4.0.0&&< 4.0.64.0.6org.springframework.boot:spring-boot:4.0.6

Affected Products

1 product · 1 configurations
Application
spring bootvmware
≥ 4.0.0 && < 4.0.6
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.springframework.boot:spring-boot, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.springframework.boot:spring-boot to 4.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40976 is resolved across your whole dependency graph.

  3. Workarounds

    Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This is an Important flaw in Spring Boot that allows security bypass under specific application configurations. When a servlet-based web application lacks custom Spring Security configuration, relies on the default web security filter chain, depends on `spring-boot-actuator-autoconfigure`, and does not include…

Workaround published by Red Hat
To mitigate this flaw, ensure that Spring Boot applications either implement their own Spring Security configuration, thereby not relying on the default web security filter chain, or include a dependency on `spring-boot-health`. Applications that do not meet all the specific conditions outlined for vulnerability are not affected. If `spring-boot-actuator-autoconfigure` is not strictly required, consider removing it.
Source: Red Hat security advisory for CVE-2026-40976 (CC BY 4.0)

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

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CVE-2026-40976: spring-boot — Fixed in 4.0.6