# CVE-2026-40971: Spring Boot's RabbitMQ auto-configuration doesn't perform hostname verification when connecting to the RabbitMQ broker

> Attackers can bypass SSL hostname verification in Spring Boot RabbitMQ connections, enabling man-in-the-middle attacks when SSL bundles are configured.

- **Severity:** Medium 5.0 (`CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Apr 2026
- **Updated:** 28 Apr 2026
- **Also known as:** GHSA-9vc8-qppq-wvxc

## What is CVE-2026-40971?

CVE-2026-40971 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 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.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-40971?

4 open source packages ship an affected version, including org.springframework.boot:spring-boot-rabbitmq. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.springframework.boot:spring-boot-rabbitmq` | Maven | From 3.5.0 | 3.5.14 |
| `org.springframework.boot:spring-boot-rabbitmq` | Maven | From 3.5.0 | 3.5.14 |
| `org.springframework.boot:spring-boot-rabbitmq` | Maven | From 4.0.0 | 4.0.6 |
| `org.springframework.boot:spring-boot-rabbitmq` | Maven | From 4.0.0 | 4.0.6 |

Products: Vmware Spring Boot.

## How do I fix CVE-2026-40971?

Upgrade org.springframework.boot:spring-boot-rabbitmq to a fixed version for your release line: 3.5.14 or 4.0.6.

## Is CVE-2026-40971 being exploited?

There is no known exploitation of CVE-2026-40971 in the wild and no public exploit code.

## Other vulnerabilities in Spring Boot

- [CVE-2023-20873](https://insights.sbomify.com/CVE-2023-20873/): Spring Boot Security Bypass with Wildcard Pattern Matching on Cloud Foundry (critical 9.8)
- [CVE-2026-40976](https://insights.sbomify.com/CVE-2026-40976/): Spring Boot's default security filter chain has no authorization rule with Actuator but without Health (critical 9.1)
- [CVE-2026-22731](https://insights.sbomify.com/CVE-2026-22731/): Authentication Bypass under Actuator Health groups paths (high 8.2)
- [CVE-2026-22733](https://insights.sbomify.com/CVE-2026-22733/): Authentication Bypass under Actuator CloudFoundry endpoints (high 8.2)
- [CVE-2022-27772](https://insights.sbomify.com/CVE-2022-27772/): Temporary Directory Hijacking to Local Privilege Escalation Vulnerability in org.springframework.boot:spring-boot (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40971 and fix it if it is affected.

What it is: CVE-2026-40971 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.
Exploitation: There is no known exploitation of CVE-2026-40971 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.springframework.boot:spring-boot-rabbitmq (Maven): affected from 3.5.0; fixed in 3.5.14
- org.springframework.boot:spring-boot-rabbitmq (Maven): affected from 3.5.0; fixed in 3.5.14
- org.springframework.boot:spring-boot-rabbitmq (Maven): affected from 4.0.0; fixed in 4.0.6
- org.springframework.boot:spring-boot-rabbitmq (Maven): affected from 4.0.0; fixed in 4.0.6

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-40971/ (Markdown: https://insights.sbomify.com/CVE-2026-40971/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40971
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40971
- OSV: https://osv.dev/vulnerability/CVE-2026-40971

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40971/
Summaries are generated and may contain mistakes; the official description above is the record.