diff --git a/packages/translation/src/lang/en.json b/packages/translation/src/lang/en.json
index 59f4fc071..169df14d1 100644
--- a/packages/translation/src/lang/en.json
+++ b/packages/translation/src/lang/en.json
@@ -1280,6 +1280,7 @@
       },
       "error": {
         "noUrl": "No iFrame URL provided",
+        "unsupportedProtocol": "The URL provided is using an unsupported protocol. Please use one of ({supportedProtocols})",
         "noBrowerSupport": "Your Browser does not support iframes. Please update your browser."
       }
     },
diff --git a/packages/validation/src/app.ts b/packages/validation/src/app.ts
index 507c2f8bf..dfe1a749a 100644
--- a/packages/validation/src/app.ts
+++ b/packages/validation/src/app.ts
@@ -4,7 +4,11 @@ const manageAppSchema = z.object({
   name: z.string().min(1).max(64),
   description: z.string().max(512).nullable(),
   iconUrl: z.string().min(1),
-  href: z.string().nullable(),
+  href: z
+    .string()
+    .url()
+    .regex(/^https?:\/\//) // Only allow http and https for security reasons (javascript: is not allowed)
+    .nullable(),
 });
 
 const editAppSchema = manageAppSchema.and(z.object({ id: z.string() }));
diff --git a/packages/validation/src/integration.ts b/packages/validation/src/integration.ts
index ad22d8eeb..e9606a268 100644
--- a/packages/validation/src/integration.ts
+++ b/packages/validation/src/integration.ts
@@ -7,7 +7,10 @@ import { createSavePermissionsSchema } from "./permissions";
 
 const integrationCreateSchema = z.object({
   name: z.string().nonempty().max(127),
-  url: z.string().url(),
+  url: z
+    .string()
+    .url()
+    .regex(/^https?:\/\//), // Only allow http and https for security reasons (javascript: is not allowed)
   kind: zodEnumFromArray(integrationKinds),
   secrets: z.array(
     z.object({
diff --git a/packages/validation/src/search-engine.ts b/packages/validation/src/search-engine.ts
index dbf9b0f4b..720f5fb86 100644
--- a/packages/validation/src/search-engine.ts
+++ b/packages/validation/src/search-engine.ts
@@ -5,7 +5,7 @@ import type { SearchEngineType } from "@homarr/definitions";
 
 const genericSearchEngine = z.object({
   type: z.literal("generic" satisfies SearchEngineType),
-  urlTemplate: z.string().min(1).startsWith("http").includes("%s"),
+  urlTemplate: z.string().min(1).startsWith("http").includes("%s"), // Only allow http and https for security reasons (javascript: is not allowed)
 });
 
 const fromIntegrationSearchEngine = z.object({
diff --git a/packages/widgets/src/iframe/component.tsx b/packages/widgets/src/iframe/component.tsx
index b561bd060..3f32742c7 100644
--- a/packages/widgets/src/iframe/component.tsx
+++ b/packages/widgets/src/iframe/component.tsx
@@ -1,7 +1,7 @@
 "use client";
 
 import { Box, Stack, Text, Title } from "@mantine/core";
-import { IconBrowserOff } from "@tabler/icons-react";
+import { IconBrowserOff, IconProtocol } from "@tabler/icons-react";
 
 import { objectEntries } from "@homarr/common";
 import { useI18n } from "@homarr/translation/client";
@@ -15,6 +15,9 @@ export default function IFrameWidget({ options, isEditMode }: WidgetComponentPro
   const allowedPermissions = getAllowedPermissions(permissions);
 
   if (embedUrl.trim() === "") return <NoUrl />;
+  if (!isSupportedProtocol(embedUrl)) {
+    return <UnsupportedProtocol />;
+  }
 
   return (
     <Box h="100%" w="100%">
@@ -31,6 +34,17 @@ export default function IFrameWidget({ options, isEditMode }: WidgetComponentPro
   );
 }
 
+const supportedProtocols = ["http", "https"];
+
+const isSupportedProtocol = (url: string) => {
+  try {
+    const parsedUrl = new URL(url);
+    return supportedProtocols.map((protocol) => `${protocol}:`).includes(`${parsedUrl.protocol}`);
+  } catch {
+    return false;
+  }
+};
+
 const NoUrl = () => {
   const t = useI18n();
 
@@ -42,6 +56,21 @@ const NoUrl = () => {
   );
 };
 
+const UnsupportedProtocol = () => {
+  const t = useI18n();
+
+  return (
+    <Stack align="center" justify="center" h="100%">
+      <IconProtocol />
+      <Title order={4} ta="center">
+        {t("widget.iframe.error.unsupportedProtocol", {
+          supportedProtocols: supportedProtocols.map((protocol) => protocol).join(", "),
+        })}
+      </Title>
+    </Stack>
+  );
+};
+
 const getAllowedPermissions = (permissions: Omit<WidgetComponentProps<"iframe">["options"], "embedUrl">) => {
   return objectEntries(permissions)
     .filter(([_key, value]) => value)