diff --git a/src/pretix/static/pretixpresale/js/widget/widget.js b/src/pretix/static/pretixpresale/js/widget/widget.js
index 3857b1b85b..ce984b5ab0 100644
--- a/src/pretix/static/pretixpresale/js/widget/widget.js
+++ b/src/pretix/static/pretixpresale/js/widget/widget.js
@@ -765,41 +765,11 @@ var shared_methods = {
     redeem: function (event) {
         if (this.$root.useIframe) {
             event.preventDefault();
-        } else {
-            if (this.$root.additionalURLParams) {
-                var params = new URLSearchParams(this.$root.additionalURLParams);
-                for (var [key, value] of params.entries()) {
-                    if (!event.target.form.elements[key]) {
-                        var input = document.createElement("input");
-                        input.type = "hidden";
-                        input.name = key;
-                        input.value = value;
-                        event.target.form.appendChild(input);
-                    }
-                }
-            }
-            return;
+            this.voucher_open(this.voucher);
         }
-        var redirect_url = this.$root.voucherFormTarget + '&voucher=' + encodeURIComponent(this.voucher) + '&subevent=' + this.$root.subevent;
-        if (this.$root.widget_data) {
-            redirect_url += '&widget_data=' + encodeURIComponent(this.$root.widget_data_json);
-        }
-        if (this.$root.additionalURLParams) {
-            redirect_url += '&' + this.$root.additionalURLParams;
-        }
-        redirect_url += this.$root.consent_parameter;
-        this.$root.overlay.frame_src = redirect_url;
     },
     voucher_open: function (voucher) {
-        var redirect_url;
-        redirect_url = this.$root.voucherFormTarget + '&voucher=' + encodeURIComponent(voucher);
-        if (this.$root.widget_data) {
-            redirect_url += '&widget_data=' + encodeURIComponent(this.$root.widget_data_json);
-        }
-        if (this.$root.additionalURLParams) {
-            redirect_url += '&' + this.$root.additionalURLParams;
-        }
-        redirect_url += this.$root.consent_parameter;
+        var redirect_url = this.$root.voucherFormTarget + '&voucher=' + encodeURIComponent(voucher);
         if (this.$root.useIframe) {
             this.$root.overlay.frame_src = redirect_url;
         } else {
@@ -1075,10 +1045,7 @@ Vue.component('pretix-widget-event-form', {
         + '<div class="pretix-widget-voucher-input-wrap">'
         + '<input class="pretix-widget-voucher-input" ref="voucherinput" type="text" v-model="$parent.voucher" name="voucher" placeholder="'+strings.voucher_code+'">'
         + '</div>'
-        + '<input type="hidden" name="subevent" :value="$root.subevent" />'
-        + '<input type="hidden" name="widget_data" :value="$root.widget_data_json" />'
-        + '<input v-if="$root.consent_parameter_value" type="hidden" name="consent" :value="$root.consent_parameter_value" />'
-        + '<input type="hidden" name="locale" value="' + lang + '" />'
+        + '<input type="hidden" v-for="p in hiddenParams" :name="p[0]" :value="p[1]" />'
         + '<div class="pretix-widget-voucher-button-wrap">'
         + '<button @click="$parent.redeem">' + strings.redeem + '</button>'
         + '</div>'
@@ -1136,7 +1103,13 @@ Vue.component('pretix-widget-event-form', {
             } else {
                 return strings.buy;
             }
-        }
+        },
+        hiddenParams: function () {
+            var params = new URL(this.$root.voucherFormTarget).searchParams;
+            params.delete("iframe");
+            params.delete("take_cart_id");
+            return [...params.entries()];
+        },
     },
     methods: {
         focus_voucher_field: function() {
@@ -1973,6 +1946,9 @@ var shared_root_computed = {
         if (this.subevent) {
             form_target += "&subevent=" + this.subevent;
         }
+        if (this.$root.widget_data) {
+            form_target += '&widget_data=' + encodeURIComponent(this.$root.widget_data_json);
+        }
         form_target += this.$root.consent_parameter;
         if (this.$root.additionalURLParams) {
             form_target += '&' + this.$root.additionalURLParams;