CVE-2026-40970 Spring Boot's Elasticsearch auto-configuration doesn't perform hostname verification when connecting to the Elasticsearch server.
Attackers can bypass SSL hostname verification in Spring Boot Elasticsearch connections, enabling man-in-the-middle attacks to intercept or read sensitive data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40970?
CVE-2026-40970 is a medium-severity vulnerability in Spring Boot, published on 27 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
When configured to use an SSL bundle, Spring Boot's Elasticsearch auto-configuration does not perform hostname verification when connecting to the Elasticsearch server.
Affected: Spring Boot 4.0.0–4.0.5; upgrade to 4.0.6 or later per vendor advisory.
Weakness: CWE-295
Which versions are affected by CVE-2026-40970?
2 open source packages ship an affected version, including org.springframework.boot:spring-boot-elasticsearch. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.springframework.boot:spring-boot-elasticsearch Maven | From 4.0.0 | 4.0.6 |
org.springframework.boot:spring-boot-elasticsearch Maven | From 4.0.0 | 4.0.6 |
Products include Vmware Spring Boot.
How do I fix CVE-2026-40970?
Upgrade org.springframework.boot:spring-boot-elasticsearch to 4.0.6 or later.
Is CVE-2026-40970 being exploited?
There is no known exploitation of CVE-2026-40970 in the wild and no public exploit code.
Other vulnerabilities in Spring Boot
- CVE-2023-20873 Spring Boot Security Bypass with Wildcard Pattern Matching on Cloud Foundry
- CVE-2026-40976 Spring Boot's default security filter chain has no authorization rule with Actuator but without Health
- CVE-2026-22731 Authentication Bypass under Actuator Health groups paths
- CVE-2026-22733 Authentication Bypass under Actuator CloudFoundry endpoints
- CVE-2022-27772 Temporary Directory Hijacking to Local Privilege Escalation Vulnerability in org.springframework.boot:spring-boot
Sources
Also known as GHSA-c96x-rpm4-349p.