diff --git a/internal/runnerfacade/facade_test.go b/internal/runnerfacade/facade_test.go
index 87e6d66..6300842 100644
--- a/internal/runnerfacade/facade_test.go
+++ b/internal/runnerfacade/facade_test.go
@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"net/url"
+	"strings"
 	"testing"
 
 	"connectrpc.com/connect"
@@ -131,9 +132,11 @@ func TestAPIHandlerMatchesOfficialRunnerBasePath(t *testing.T) {
 }
 
 func TestHandlerProxiesRepositoryTrafficToGitea(t *testing.T) {
-	upstream := httptest.NewServer(http.HandlerFunc(func(response http.ResponseWriter, request *http.Request) {
-		if request.URL.Path != "/owner/repo/info/refs" || request.Header.Get("Authorization") != "Basic checkout-token" {
-			t.Errorf("request path=%q authorization=%q", request.URL.Path, request.Header.Get("Authorization"))
+	var upstream *httptest.Server
+	upstream = httptest.NewServer(http.HandlerFunc(func(response http.ResponseWriter, request *http.Request) {
+		upstreamHost := strings.TrimPrefix(upstream.URL, "http://")
+		if request.URL.Path != "/owner/repo/info/refs" || request.Header.Get("Authorization") != "Basic checkout-token" || request.Host != upstreamHost {
+			t.Errorf("request path=%q authorization=%q host=%q", request.URL.Path, request.Header.Get("Authorization"), request.Host)
 			response.WriteHeader(http.StatusBadRequest)
 			return
 		}
diff --git a/internal/runnerfacade/server.go b/internal/runnerfacade/server.go
index 95384c7..ecccca1 100644
--- a/internal/runnerfacade/server.go
+++ b/internal/runnerfacade/server.go
@@ -39,7 +39,13 @@ func Handler(facade *Facade, upstreamURL string) (http.Handler, error) {
 	path, service := facade.Handler()
 	mux := http.NewServeMux()
 	mux.Handle(APIBasePath+path, http.StripPrefix(APIBasePath, SPIFFEMiddleware(service)))
-	mux.Handle("/", httputil.NewSingleHostReverseProxy(target))
+	proxy := httputil.NewSingleHostReverseProxy(target)
+	director := proxy.Director
+	proxy.Director = func(request *http.Request) {
+		director(request)
+		request.Host = target.Host
+	}
+	mux.Handle("/", proxy)
 	return mux, nil
 }