CVE-2026-40971

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-27 · updated 2026-07-24
Weakness: CWE-295

Description

When configured to use an SSL bundle, Spring Boot's RabbitMQ auto-configuration does not perform hostname verification when connecting to the RabbitMQ broker. Affected: Spring Boot 4.0.0–4.0.5 (fix 4.0.6), 3.5.0–3.5.13 (fix 3.5.14) per vendor advisory.

Affected products

Spring Boot: from 3.5.0 before 3.5.14; from 4.0.0 before 4.0.6 — fixed in 3.5.14, 4.0.6
Spring Boot: from 4.0.0 before 4.0.6; from 3.5.0 before 3.5.14 — fixed in 4.0.6, 3.5.14

How to fix

Upgrade to a fixed version: Spring Boot 3.5.14, 4.0.6; Spring Boot 4.0.6, 3.5.14. Check the vendor advisory for mitigations.

References

https://spring.io/security/cve-2026-40971

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