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Spring BootFramework / library · VMware

CVE-2026-40970

MEDIUM · 6.8 CVSS v3.1 Published 2026-04-27
Fix available
A fix is available. Upgrade to 4.0.6 or later.
See remediation →
73/100
Remediation priority · Elevated
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
When configured to use an SSL bundle, Spring Boot's Elasticsearch auto-configuration does not perform hostname verification when connecting to the Elasticsearch server. Affected: Spring Boot 4.0.0–4.0.5; upgrade to 4.0.6 or later per vendor advisory.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Spring Boot's Elasticsearch auto-configuration skips SSL hostname verification when configured to use an SSL bundle, allowing man-in-the-middle attackers to intercept encrypted Elasticsearch communications. This affects versions 4.0.0 through 4.0.5.

MitigationUpgrade Spring Boot to version 4.0.6 or later to receive the patch that re-enables proper hostname verification for SSL connections.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Spring BootFramework / library
Affected:>= 4.0.0, < 4.0.6

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Spring Boot version
    Check your project's build configuration (pom.xml, build.gradle, or gradle.properties) for the spring-boot-starter-parent version or the spring-boot-version property. Also check the JAR manifest or run: java -jar your-app.jar --version
    Affected if Version is 4.0.0, 4.0.1, 4.0.2, 4.0.3, 4.0.4, or 4.0.5
  2. Confirm Elasticsearch auto-configuration usage
    Check your project dependencies for spring-boot-starter-data-elasticsearch or spring-boot-starter-autoconfigure. Also verify that Elasticsearch repositories or ElasticsearchRestTemplate beans are being used in your code.
    Affected if Spring Data Elasticsearch auto-configuration is enabled in the application
  3. Verify SSL bundle configuration for Elasticsearch
    Inspect your application.properties or application.yml configuration files for elasticsearch.ssl.bundle or related SSL configuration properties under the elasticsearch namespace.
    Affected if An SSL bundle is configured for Elasticsearch connections (e.g., elasticsearch.ssl.bundle property is set)
  4. Check if SSL is actually in use
    Review your Elasticsearch connection configuration to determine if SSL/TLS is enabled for the connection. Look for https:// URLs in connection strings or ssl: true settings in your configuration.
    Affected if SSL/TLS is enabled for the Elasticsearch connection

Affected if running Spring Boot version 4.0.0 through 4.0.5 AND using Elasticsearch auto-configuration with an SSL bundle configured for encrypted connections.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.0.6 or later
Fixed in 4.0.6
Interim mitigation

Upgrade Spring Boot to version 4.0.6 or later to receive the patch that re-enables proper hostname verification for SSL connections.

Recommended fix High confidence

Spring Boot 4.0.6

  1. 1. Update the Spring Boot version in your project's pom.xml or build.gradle file from 4.0.0-4.0.5 to 4.0.6
  2. 2. Rebuild and test your application to ensure compatibility with the new version
  3. 3. Verify that Elasticsearch connections with SSL bundles now properly perform hostname verification

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Spring Boot Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,120
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,392.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40970 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data