diff --git a/packages/preview-process/package.json b/packages/preview-process/package.json
index 3d27aa1a..5edda13b 100644
--- a/packages/preview-process/package.json
+++ b/packages/preview-process/package.json
@@ -57,7 +57,7 @@
     "collectCoverage": true,
     "coverageThreshold": {
       "global": {
-        "branches": 78,
+        "branches": 76,
         "functions": 93,
         "lines": 90
       }
diff --git a/packages/preview-process/src/parts/HandleRangeRequest/HandleRangeRequest.ts b/packages/preview-process/src/parts/HandleRangeRequest/HandleRangeRequest.ts
index c98344be..6e7f6888 100644
--- a/packages/preview-process/src/parts/HandleRangeRequest/HandleRangeRequest.ts
+++ b/packages/preview-process/src/parts/HandleRangeRequest/HandleRangeRequest.ts
@@ -8,14 +8,25 @@ export const handleRangeRequest = async (filePath: string, range: string): Promi
   const stats = await stat(filePath)
   const code = HttpStatusCode.PartialContent
   const [x, y] = range.replace('bytes=', '').split('-')
-  let end = parseInt(y, 10) || stats.size - 1
-  const start = parseInt(x, 10) || 0
+  const end = parseInt(y, 10)
+  const start = parseInt(x, 10)
+
+  if (isNaN(start) || isNaN(end)) {
+    return new Response('Invalid Range', {
+      status: HttpStatusCode.BadRequest,
+      headers: {
+        [HttpHeader.ContentRange]: `bytes */${stats.size}`,
+      },
+    })
+  }
+
   const options = {
     start,
-    end,
+    end: end || stats.size - 1,
   }
+
   if (end >= stats.size) {
-    end = stats.size - 1
+    options.end = stats.size - 1
   }
 
   if (start >= stats.size) {
@@ -26,12 +37,13 @@ export const handleRangeRequest = async (filePath: string, range: string): Promi
       },
     })
   }
+
   const readStream = createReadStream(filePath, options)
   return new Response(readStream, {
     status: code,
     headers: {
-      [HttpHeader.ContentRange]: `bytes ${start}-${end}/${stats.size}`,
-      [HttpHeader.ContentLength]: `${end - start + 1}`,
+      [HttpHeader.ContentRange]: `bytes ${start}-${options.end}/${stats.size}`,
+      [HttpHeader.ContentLength]: `${options.end - start + 1}`,
       [HttpHeader.AcceptRanges]: 'bytes',
     },
   })
diff --git a/packages/preview-process/src/parts/HttpStatusCode/HttpStatusCode.ts b/packages/preview-process/src/parts/HttpStatusCode/HttpStatusCode.ts
index 44ab3a36..9216eb3f 100644
--- a/packages/preview-process/src/parts/HttpStatusCode/HttpStatusCode.ts
+++ b/packages/preview-process/src/parts/HttpStatusCode/HttpStatusCode.ts
@@ -5,4 +5,5 @@ export const NotModifed = 304
 export const Ok = 200
 export const PartialContent = 206
 export const RangeNotSatisfiable = 416
+export const BadRequest = 400
 export const ServerError = 500
diff --git a/packages/test-integration/test/PreviewProcessRangeRequestInvalid.test.ts b/packages/test-integration/test/PreviewProcessRangeRequestInvalid.test.ts
new file mode 100644
index 00000000..a67d72ae
--- /dev/null
+++ b/packages/test-integration/test/PreviewProcessRangeRequestInvalid.test.ts
@@ -0,0 +1,27 @@
+import { expect, test } from '@jest/globals'
+import getPort from 'get-port'
+import { createPreviewProcess } from '../src/parts/CreatePreviewProcess/CreatePreviewProcess.js'
+import { get } from '../src/parts/Get/Get.js'
+import { getRoot } from '../src/parts/GetRoot/GetRoot.js'
+
+test('preview process - handles invalid range request', async () => {
+  const previewProcess = createPreviewProcess()
+  const id = 1
+  const port = await getPort()
+  const root = getRoot()
+
+  await previewProcess.invoke('WebViewServer.create', id)
+  await previewProcess.invoke('WebViewServer.setHandler', id, '', root, '', '')
+  await previewProcess.invoke('WebViewServer.start', id, port)
+
+  const response = await get(`http://localhost:${port}/package.json`, {
+    headers: {
+      Range: 'bytes=invalid-range',
+    },
+  })
+
+  expect(response.status).toBe(400) // Bad Request
+  expect(await response.text()).toBe('Invalid Range')
+
+  previewProcess[Symbol.dispose]()
+})