CVE-2026-40992: Spring Boot's Mail Auto-Configuration Does Not Enable SSL Hostname Verification

June 11, 2026 (updated August 18, 2026)

Spring Boot’s Mail auto-configuration does not enable hostname verification. Applications that set the relevant JavaMail property, such as spring.mail.properties.mail.smtp.ssl.checkserveridentity=true, are not affected.

Affected versions: Spring Boot 4.0.0 through 4.0.6; 3.5.0 through 3.5.14; 3.4.0 through 3.4.16.

References

github.com/advisories/GHSA-9wxp-w4px-32vh
nvd.nist.gov/vuln/detail/CVE-2026-40992
spring.io/security/cve-2026-40992

Code Behaviors & Features

Detect and mitigate CVE-2026-40992 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Learn more about Dependency Scanning →