Nginx UI: Unauthenticated signed-request body staging can exhaust temporary storage

Nginx UI is a web user interface for the Nginx web server. From 2.5.0 until 2.6.0, the node-signature authentication path performs temporary file staging of an attacker-controlled request body and synchronizes it before validating the body digest and cryptographic signature. An unauthenticated remote client that can reach the API and provide syntactically valid signature metadata can consume temporary filesystem capacity, disk input and output, and request-processing resources before rejection. The issue affects availability and does not bypass authentication or provide confidentiality or integrity impact. This issue is fixed in version 2.6.0.