Rucio: Authorisation Bypass on REST API endpoint for signing URLs

Rucio is a scientific data management framework. From 1.16.1 until 35.9.0, 38.6.0, and 41.0.0rc1, the /credentials/signurl endpoint reads X-Rucio-Account instead of the account stored in request.environ['issuer'] by token authentication. Any authenticated low-privilege user can supply root as the header value and pass the root-only get_signed_url permission check. The server then returns a presigned read, write, or delete URL for an attacker-selected object using stored S3, GCS, or Swift credentials, and X-Rucio-VO can select another tenant in multi-VO deployments. This permits data disclosure, modification, deletion, and cross-tenant access on cloud-backed RSEs. This issue is fixed in versions 35.9.0, 38.6.0, and 41.0.0rc1.