CVE-2026-40992 PUBLISHED

Mail Auto-Configuration Does Not Enable SSL Hostname Verification

Assigner: vmware
Reserved: 16.04.2026 Published: 11.06.2026 Updated: 11.06.2026

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.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
CVSS Score: 5

Attack Vector	Adjacent Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	Low
Privileges Required	None	Integrity Impact	Low
User Interaction	None	Availability Impact	Low

CVSS 3.1

Product Status

Vendor	Spring
Product	Spring Boot
Versions	Default: unaffected affected from 4.0.0 to 4.0.7 (excl.) affected from 3.5.0 to 3.5.15 (excl.) affected from 3.4.0 to 3.4.17 (excl.)

References

https://spring.io/security/cve-2026-40992

Problem Types

CWE-295: Improper Certificate Validation CWE

Impacts

A network attacker in a man-in-the-middle position on the mail submission path can intercept or tamper with mail traffic because Spring Boot Mail auto-configuration does not enable SSL hostname verification.