diff --git a/web/app/components/base/prompt-editor/plugins/hitl-input-block/__tests__/input-field.spec.tsx b/web/app/components/base/prompt-editor/plugins/hitl-input-block/__tests__/input-field.spec.tsx
index e97fc19f71..c6905da9f7 100644
--- a/web/app/components/base/prompt-editor/plugins/hitl-input-block/__tests__/input-field.spec.tsx
+++ b/web/app/components/base/prompt-editor/plugins/hitl-input-block/__tests__/input-field.spec.tsx
@@ -11,6 +11,7 @@ type VarReferencePickerProps = {
 }
 
 let lastVarReferencePickerProps: VarReferencePickerProps | undefined
+let fileUploadSettingMaxLength: number | undefined = 4
 
 vi.mock('@/app/components/workflow/nodes/_base/components/variable/var-reference-picker', () => ({
   default: (props: VarReferencePickerProps) => {
@@ -66,7 +67,7 @@ vi.mock('@/app/components/workflow/nodes/_base/components/file-upload-setting',
         allowed_file_extensions: ['.pdf'],
         allowed_file_types: [SupportUploadFileTypes.document],
         allowed_file_upload_methods: [TransferMethod.local_file],
-        max_length: 4,
+        max_length: fileUploadSettingMaxLength,
       })}
     >
       file-upload-setting
@@ -89,6 +90,7 @@ describe('InputField', () => {
   beforeEach(() => {
     vi.clearAllMocks()
     lastVarReferencePickerProps = undefined
+    fileUploadSettingMaxLength = 4
   })
 
   it('should keep the header and actions visible while the field content scrolls internally', () => {
@@ -627,6 +629,32 @@ describe('InputField', () => {
     })
   })
 
+  it('should normalize empty file-list upload limit on save', async () => {
+    const user = userEvent.setup()
+    const onChange = vi.fn()
+    fileUploadSettingMaxLength = Number.NaN
+
+    render(
+      <InputField
+        nodeId="node-14-normalize"
+        isEdit={false}
+        payload={createPayload()}
+        onChange={onChange}
+        onCancel={vi.fn()}
+      />,
+    )
+
+    await user.click(screen.getByRole('button', { name: 'select-file-list' }))
+    await user.click(screen.getByRole('button', { name: 'file-upload-setting' }))
+    await user.click(screen.getByRole('button', { name: /workflow\.nodes\.humanInput\.insertInputField\.insert/i }))
+
+    expect(onChange).toHaveBeenCalledTimes(1)
+    expect(onChange.mock.calls[0]![0]).toEqual(expect.objectContaining({
+      type: InputVarType.multiFiles,
+      number_limits: 1,
+    }))
+  })
+
   it('should clear paragraph default state when switching to file-list', async () => {
     const user = userEvent.setup()
     const onChange = vi.fn()
diff --git a/web/app/components/base/prompt-editor/plugins/hitl-input-block/input-field.tsx b/web/app/components/base/prompt-editor/plugins/hitl-input-block/input-field.tsx
index e5393ee387..6d7ad432db 100644
--- a/web/app/components/base/prompt-editor/plugins/hitl-input-block/input-field.tsx
+++ b/web/app/components/base/prompt-editor/plugins/hitl-input-block/input-field.tsx
@@ -97,6 +97,16 @@ const InputField: React.FC<InputFieldProps> = ({
   const handleSave = useCallback(() => {
     if (!nameValid)
       return
+    if (isFileListFormInput(tempPayload)) {
+      const value = tempPayload.number_limits ?? 5
+      if (!Number.isFinite(value)) {
+        onChange({
+          ...tempPayload,
+          number_limits: 1,
+        })
+        return
+      }
+    }
     onChange(tempPayload)
   }, [nameValid, onChange, tempPayload])
   const handleTypeChange = useCallback((item: TypeSelectItem) => {
diff --git a/web/app/components/workflow/nodes/_base/components/__tests__/file-support.spec.tsx b/web/app/components/workflow/nodes/_base/components/__tests__/file-support.spec.tsx
index 1a3e004c7e..c330e0caed 100644
--- a/web/app/components/workflow/nodes/_base/components/__tests__/file-support.spec.tsx
+++ b/web/app/components/workflow/nodes/_base/components/__tests__/file-support.spec.tsx
@@ -1,6 +1,7 @@
 import type { UploadFileSetting } from '@/app/components/workflow/types'
 import { fireEvent, render, screen } from '@testing-library/react'
 import userEvent from '@testing-library/user-event'
+import { useState } from 'react'
 import { useFileSizeLimit } from '@/app/components/base/file-uploader/hooks'
 import { SupportUploadFileTypes } from '@/app/components/workflow/types'
 import { useFileUploadConfig } from '@/service/use-common'
@@ -120,6 +121,35 @@ describe('File upload support components', () => {
       }))
     })
 
+    it('should keep upload limits within the configured range', () => {
+      const StatefulFileUploadSetting = () => {
+        const [payload, setPayload] = useState(createPayload())
+
+        return (
+          <FileUploadSetting
+            payload={payload}
+            isMultiple
+            onChange={setPayload}
+          />
+        )
+      }
+
+      render(<StatefulFileUploadSetting />)
+
+      const input = screen.getByRole('spinbutton')
+
+      fireEvent.change(input, { target: { value: '20' } })
+      expect(input).toHaveValue(10)
+
+      fireEvent.change(input, { target: { value: '0' } })
+      expect(input).toHaveValue(1)
+
+      fireEvent.change(input, { target: { value: '' } })
+      expect(input).toHaveValue(null)
+      fireEvent.blur(input)
+      expect(input).toHaveValue(1)
+    })
+
     it('should toggle built-in and custom file type selections', async () => {
       const user = userEvent.setup()
       const onChange = vi.fn()
diff --git a/web/app/components/workflow/nodes/_base/components/file-upload-setting.tsx b/web/app/components/workflow/nodes/_base/components/file-upload-setting.tsx
index 3a9af99538..77e7de851e 100644
--- a/web/app/components/workflow/nodes/_base/components/file-upload-setting.tsx
+++ b/web/app/components/workflow/nodes/_base/components/file-upload-setting.tsx
@@ -89,11 +89,14 @@ const FileUploadSetting: FC<Props> = ({
   }, [onChange, payload])
 
   const handleMaxUploadNumLimitChange = useCallback((value: number) => {
+    const normalizedValue = Number.isFinite(value)
+      ? Math.min(Math.max(value, 1), maxFileUploadLimit)
+      : value
     const newPayload = produce(payload, (draft) => {
-      draft.max_length = value
+      draft.max_length = normalizedValue
     })
     onChange(newPayload)
-  }, [onChange, payload])
+  }, [maxFileUploadLimit, onChange, payload])
 
   return (
     <div>
@@ -163,6 +166,7 @@ const FileUploadSetting: FC<Props> = ({
             <InputNumberWithSlider
               label={t('variableConfig.maxNumberOfUploads', { ns: 'appDebug' })!}
               value={max_length}
+              defaultValue={1}
               min={1}
               max={maxFileUploadLimit}
               onChange={handleMaxUploadNumLimitChange}