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.
Exploitability
AV:AAC:HPR:NUI:NScope
S:UImpact
C:LI:LA:L5/CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:LCryptography