Improper Validation of Certificate with Host Mismatch Affecting org.springframework.boot:spring-boot-elasticsearch package, versions [,4.0.6)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published24 Apr 2026
- disclosed23 Apr 2026
- creditYu Bao
Introduced: 23 Apr 2026
CVE-2026-40970 (opens in a new tab)How to fix?
Upgrade org.springframework.boot:spring-boot-elasticsearch to version 4.0.6 or higher.
Overview
Affected versions of this package are vulnerable to Improper Validation of Certificate with Host Mismatch during the TLS handshake. When Spring Boot is configured to connect to Elasticsearch using an SSL bundle, the auto-configuration fails to verify that the hostname in the server's SSL certificate matched the actual hostname being connected to. While the certificate's signature and expiration might be validated, failing to check the hostname means an attacker could present any certificate signed by a trusted Certificate Authority (even one registered to an entirely different domain) and successfully intercept the traffic. This exposes the application to Man-in-the-Middle (MitM) attacks.