CVE-2026-40976
CriticalWhat is 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.
CVSS Vector Breakdown
CVSS 3.1Exploitable remotely over the network without requiring access to the local system.
No special conditions required. Exploit can be performed reliably and repeatedly.
No authentication required. Any anonymous user can exploit this vulnerability.
No user interaction required. Exploit runs without any victim action.
Exploiting the vulnerability only affects the vulnerable component itself.
Complete loss of confidentiality. All data on the component may be exposed.
Complete loss of integrity. Attacker can modify any file or data on the component.
No availability impact. Service remains fully operational.
FAQ
CVE-2026-40976 has a CVSS score of 9.1/10, rated as Critical. This is the highest severity level - immediate patching is strongly recommended.
CVSS (Common Vulnerability Scoring System) rates vulnerability severity from 0.0 to 10.0. CVE-2026-40976 scores 9.1/10 (Critical). Scores 9.0–10.0 are Critical, 7.0–8.9 are High, 4.0–6.9 are Medium, and below 4.0 are Low.
The list of devices confirmed to be affected by CVE-2026-40976 is shown in the "Affected Devices" section above. Check your firmware version against the vendor security advisory and apply the latest patch.
Apply the latest firmware or software update from the vendor. Check the References section above for official advisories and patch notes. If no patch is available, consider disabling the affected feature or isolating the device from untrusted networks.