CVE-2026-94571: critical vulnerability in OpenStack Octavia

In OpenStack Octavia before 18.0.1, the Amphora provider driver did not reject control characters in the L7 policy redirect_url and redirect_prefix fields. The RFC 3986 URL validator percent-encodes control characters before validating, and thus newlines passed structural checks, but Octavia stored and wrote the raw unencoded value directly into the HAProxy configuration generated on the amphora. An authenticated project member who owns a load balancer can therefore inject arbitrary HAProxy directives through a REDIRECT_TO_URL L7 policy. Only deployments using the Amphora provider are affected.