How to Fix CVE-2026-40976: Spring Boot (Bundle Sibling)
By Sai Kiran Pandrala
Last verified: 2026-05-25
CVE-2026-40976 is a sibling vulnerability in the same vendor advisory as CVE-2026-40970. Applying the patched build named in the primary write-up closes this CVE as well.
| Severity | CVSS 9.1 - Critical |
|---|---|
| Actively exploited? | Not currently in CISA KEV |
| Affected | Same as the bundle - see CVE-2026-40970 |
| Fixed in | Same patched build as CVE-2026-40970 (See vendor advisory) |
| Type (CWE) | CWE-862: CWE-862: Missing Authorization |
What's different about CVE-2026-40976?
In certain circumstances, Spring Boot's default web security is ineffective allowing unauthorized access to all endpoints. For an application to be vulnerable, it must: be a servlet-based web application; have no Spring Security configuration of its own and rely on the default web security filter chain; depend on spring-boot-actuator-autoconfigure; not depend on spring-boot-health. If any of the above does not apply, the application is not vulnerable.
Affected: Spring Boot 4.0.0–4.0.5; upgrade to 4.0.6 or later per vendor advisory.
The technical impact and remediation are identical to the primary CVE in the bundle. The same vendor patch closes both.
How to fix CVE-2026-40976
Apply the patched build per the primary write-up: How to Fix CVE-2026-40970.
The patch installation procedure, verification commands, and interim mitigations are documented there. Reusing one runbook keeps the rollout consistent across the bundle.
Frequently asked questions
Is CVE-2026-40976 fixed by the same patch as CVE-2026-40970?
Yes. CVE-2026-40976 ships in the same vendor advisory as CVE-2026-40970. Applying the patched build named in the primary write-up closes both.
What is the CVSS score for CVE-2026-40976?
The CVSS base score is 9.1 (Critical).
Is it being exploited?
It is not currently listed in CISA KEV.
References
- Official vendor advisory: https://spring.io/security/cve-2026-40976
- NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-40976
- CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- Primary write-up: How to Fix CVE-2026-40970
*Part of the Spring Boot bundle. Full procedure at CVE-2026-40970.*