oras-go is a Go library for managing OCI artifacts. Prior to 2.6.1, registry/remote/repository.go in blobStore.completePushAfterInitialPost follows a registry-controlled Location header during monolithic blob upload and reuses the Authorization header from the initial POST request for the subsequent PUT request, allowing a malicious registry to return a cross-host Location and receive the callers credentials at an attacker-controlled endpoint. This issue is fixed in version 2.6.1.
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.