diff --git a/app_web/src/main.js b/app_web/src/main.js
index a2d07d89..62b66a2d 100644
--- a/app_web/src/main.js
+++ b/app_web/src/main.js
@@ -3,8 +3,8 @@ import { GltfView } from 'gltf-viewer-source';
 
 import { UIModel } from './logic/uimodel.js';
 import { app } from './ui/ui.js';
-import { from, merge } from 'rxjs';
-import { mergeMap, map, share } from 'rxjs/operators';
+import { EMPTY, from, merge } from 'rxjs';
+import { mergeMap, map, share, catchError } from 'rxjs/operators';
 import { GltfModelPathProvider, fillEnvironmentWithPaths } from './model_path_provider.js';
 
 export default async () => {
@@ -72,6 +72,11 @@ export default async () => {
                 return state;
             }));
         }),
+        catchError(error => {
+            console.error(error);
+            uiModel.exitLoadingState();
+            return EMPTY;
+        }),
         share()
     );
 
diff --git a/source/gltf/gltf.js b/source/gltf/gltf.js
index f6f9e9e0..9253c3e6 100644
--- a/source/gltf/gltf.js
+++ b/source/gltf/gltf.js
@@ -18,6 +18,27 @@ import { gltfAnimation } from './animation.js';
 import { gltfSkin } from './skin.js';
 import { gltfVariant } from './variant.js';
 
+const allowedExtensions = [
+    "KHR_draco_mesh_compression",
+    "KHR_texture_basisu",
+    "KHR_texture_transform",
+    "KHR_lights_punctual",
+    "KHR_lights_image_based",
+    "KHR_materials_variants",
+    "KHR_materials_unlit",
+    "KHR_materials_clearcoat",
+    "KHR_materials_sheen",
+    "KHR_materials_transmission",
+    "KHR_materials_volume",
+    "KHR_materials_ior",
+    "KHR_materials_iridescence",
+    "KHR_materials_anisotropy",
+    "KHR_materials_specular",
+    "KHR_materials_emissive_strength",
+    "KHR_materials_xmp_json_ld",
+    "KHR_materials_pbrSpecularGlossiness",
+];
+
 class glTF extends GltfObject
 {
     constructor(file)
@@ -52,6 +73,12 @@ class glTF extends GltfObject
     {
         super.fromJson(json);
 
+        for (const extensionName of json.extensionsRequired ?? []) {
+            if (!allowedExtensions.includes(extensionName)) {
+                throw new Error("Unsupported extension: " + extensionName);
+            }
+        }
+
         this.asset = objectFromJson(json.asset, gltfAsset);
         this.cameras = objectsFromJsons(json.cameras, gltfCamera);
         this.accessors = objectsFromJsons(json.accessors, gltfAccessor);