diff --git a/mod_http2/mod_proxy_http2.c b/mod_http2/mod_proxy_http2.c
index 893aa8f..d52d5d9 100644
--- a/mod_http2/mod_proxy_http2.c
+++ b/mod_http2/mod_proxy_http2.c
@@ -154,11 +154,25 @@ static int proxy_http2_canon(request_rec *r, char *url)
         if (apr_table_get(r->notes, "proxy-nocanon")) {
             path = url;   /* this is the raw path */
         }
+        else if (apr_table_get(r->notes, "proxy-noencode")) {
+            path = url;   /* this is the encoded path already */
+            search = r->args;
+        }
         else {
             path = ap_proxy_canonenc(r->pool, url, (int)strlen(url),
                                      enc_path, 0, r->proxyreq);
             search = r->args;
         }
+        if (search && *ap_scan_vchar_obstext(search)) {
+            /*
+             * We have a raw control character or a ' ' in r->args.
+             * Correct encoding was missed.
+             */
+            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(10412)
+                          "To be forwarded query string contains control "
+                          "characters or spaces");
+            return HTTP_FORBIDDEN;
+        }
         break;
     case PROXYREQ_PROXY:
         path = url;