Cyber Resilience

CVE-2026-40971

Medium

Published: 27 April 2026

Published
27 April 2026
Modified
14 May 2026
KEV Added
Patch
CVSS Score v3.1 5.0 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
EPSS Score 0.0016 5.3th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-40971 is a medium-severity Improper Certificate Validation (CWE-295) vulnerability in Vmware Spring Boot. Its CVSS base score is 5.0 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Adversary-in-the-Middle (T1557); ranked at the 5.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability details

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1557 Adversary-in-the-Middle Credential Access
Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as [Network Sniffing](https://attack.
Why these techniques?

Missing hostname verification in SSL connections enables adversary-in-the-middle positioning against the RabbitMQ broker.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

Affected Assets

vmware
spring boot
3.5.0 — 3.5.14 · 4.0.0 — 4.0.6

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-295

When certificates are used to establish component provenance, the control requires correct certificate validation procedures.

addresses: CWE-295

Mandates approved trust anchors and issuance policies, directly preventing acceptance of unvalidated or untrusted certificates.

addresses: CWE-295

Correct system time is required for proper enforcement of certificate notBefore/notAfter dates and time-based revocation checks.

References