CVE-2026-40970: Elasticsearch auto-configuration with an SSL bundle disables TLS hostname verification

MEDIUM | APRIL 23, 2026 | CVE-2026-40970

Description

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 Products and Versions

Spring Boot:

  • 4.0.0 - 4.0.5

Mitigation

Users of affected versions should upgrade to the corresponding fixed version.

Affected version(s) Fix version Availability
4.0.x 4.0.6 OSS

No further mitigation steps are necessary.

Credit

Credit

The issue was identified and responsibly reported by Yu Bao (@August829) - yubao@paypal.com – who works for paypal.com.

References

History

  • 2026-04-23: Initial vulnerability report published.

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