The vulnerability exists in nginx-ui, a web user interface for the Nginx web server, in versions up to 2.3.4. It allows an authenticated user to perform SSRF by leveraging the cluster node configuration and the X-Node-ID header in API requests. The proxy middleware forwards these requests to attacker-specified internal URLs, effectively bypassing network segmentation controls. This can lead to unauthorized access to internal services that are otherwise inaccessible externally. The CVSS v3.1 score is 8.5, reflecting high impact on confidentiality and partial impact on integrity, with no impact on availability. No vendor-provided patch or official remediation is currently documented.

Successful exploitation allows an authenticated attacker to bypass network segmentation and access internal or localhost-bound services through SSRF. This can lead to unauthorized disclosure of sensitive information (high confidentiality impact) and limited modification of internal service state (low integrity impact). There is no direct impact on system availability. The vulnerability requires authentication and network access to the nginx-ui interface.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, restrict access to the nginx-ui interface to trusted users only and monitor for suspicious activity involving cluster node configurations and the X-Node-ID header. Avoid exposing the nginx-ui interface to untrusted networks. Follow vendor updates closely for any forthcoming patches or official mitigations.