diff --git a/.gitignore b/.gitignore
index e51faa6..55238c1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@
 /umd
 npm-debug.log*
 package-lock.json
+/.vscode
diff --git a/CHANGES.md b/CHANGES.md
index c7a2410..1e250dd 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,7 @@
+## 4.0.2 / 2018-02-08
+
+* Prevent paste in disabled state
+
 ## 4.0.1 / 2018-01-26 🇦🇺
 
 * Fix auto-fill scenarios by using data from `onChange` events [[#112](https://github.com/insin/react-maskedinput/pull/112)]
diff --git a/README.md b/README.md
index 7ed1291..46cca07 100644
--- a/README.md
+++ b/README.md
@@ -118,6 +118,10 @@ A default `placeholder` will be generated from the mask's pattern, but you can p
 
 By default, the rendered `<input>`'s `size` will be the length of the pattern, but you can pass a `size` prop to override this.
 
+### `onBadInput` : `() => void`
+
+A callback which will be called any time the user inputs or pastes invalid character(s).****
+
 ### Other props
 
 Any other props passed in will be passed as props to the rendered `<input>`, except for the following, which are managed by the component:
diff --git a/demo/src/index.js b/demo/src/index.js
index 54a38d6..f9e7ddf 100644
--- a/demo/src/index.js
+++ b/demo/src/index.js
@@ -1,7 +1,7 @@
 import './style.css'
 
 import React from 'react'
-import {render} from 'react-dom'
+import {render, findDOMNode} from 'react-dom'
 
 import MaskedInput from '../../src'
 
@@ -12,7 +12,7 @@ const PATTERNS = [
   '1 1',
 ]
 
-class App extends React.Component {
+class App extends React.PureComponent {
   state = {
     card: '',
     expiry: '',
@@ -43,6 +43,24 @@ class App extends React.Component {
     }
   }
 
+  _onBadInput = () => {
+    if (this.timerId) {
+      return;
+    }
+    this.inputCardNode.classList.add('is-invalid');
+    this.timerId = setTimeout(() => {
+      delete this.timerId;
+      this.inputCardNode.classList.remove('is-invalid');
+    }, 400);
+  };
+
+  componentWillUnmount() {
+    if (this.timerId) {
+      clearTimeout(this.timerId);
+      delete this.timerId;
+    }
+  };
+
   render() {
     return <div className="App">
       <h1>
@@ -51,7 +69,8 @@ class App extends React.Component {
       <p className="lead">A React component which creates a masked <code>&lt;input/&gt;</code></p>
       <div className="form-field">
         <label htmlFor="card">Card Number:</label>
-        <MaskedInput mask="1111 1111 1111 1111" name="card" id="card" size="20" value={this.state.card} onChange={this._onChange}/>
+        <MaskedInput mask="1111 1111 1111 1111" name="card" id="card" size="20" value={this.state.card} onChange={this._onChange}
+          ref={input => this.inputCardNode = findDOMNode(input)} onBadInput={this._onBadInput} />
       </div>
       <p>You can even externally update the card state like a standard input element:</p>
       <div className="form-field">
diff --git a/demo/src/style.css b/demo/src/style.css
index 0c54f0c..5e6dc8a 100644
--- a/demo/src/style.css
+++ b/demo/src/style.css
@@ -39,3 +39,8 @@ input {
 footer {
   text-align: center;
 }
+.is-invalid {
+  outline-color: #efa2a9;
+  -webkit-transition: outline-color 0.2s;
+  transition: outline-color 0.2s;
+}
\ No newline at end of file
diff --git a/package.json b/package.json
index 635086f..aa110b0 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "react-maskedinput",
-  "version": "4.0.1",
+  "version": "4.0.2",
   "description": "Masked <input/> React component",
   "main": "lib/index.js",
   "module": "es/index.js",
diff --git a/src/index.js b/src/index.js
index 80ebb94..4cbef01 100644
--- a/src/index.js
+++ b/src/index.js
@@ -55,12 +55,16 @@ function setSelection(el, selection) {
   catch (e) { /* not focused or not visible */ }
 }
 
-class MaskedInput extends React.Component {
+class MaskedInput extends React.PureComponent {
   static propTypes = {
     mask: PropTypes.string.isRequired,
-
+    onChange: PropTypes.func,
     formatCharacters: PropTypes.object,
-    placeholderChar: PropTypes.string
+    placeholderChar: PropTypes.string,
+    value: PropTypes.any,
+    placeholder: PropTypes.string,
+    size: PropTypes.oneOfType([PropTypes.number, PropTypes.string]),
+    onBadInput: PropTypes.func,
   }
 
   static defaultProps = {
@@ -202,15 +206,19 @@ class MaskedInput extends React.Component {
         this.props.onChange(e)
       }
     }
+    else {
+      this._fireBadInput()
+    }
   }
 
   _onPaste = (e) => {
     // console.log('onPaste', JSON.stringify(getSelection(this.input)), e.clipboardData.getData('Text'), e.target.value)
+    const {disabled} = this.props
 
     e.preventDefault()
     this._updateMaskSelection()
     // getData value needed for IE also works in FF & Chrome
-    if (this.mask.paste(e.clipboardData.getData('Text'))) {
+    if (!disabled && this.mask.paste(e.clipboardData.getData('Text'))) {
       e.target.value = this.mask.getValue()
       // Timeout needed for IE
       setTimeout(() => this._updateInputSelection(), 0)
@@ -243,6 +251,13 @@ class MaskedInput extends React.Component {
     }
   }
 
+  _fireBadInput () {
+    const {onBadInput} = this.props
+    if (typeof onBadInput === 'function') {
+      onBadInput()
+    }
+  }
+
   focus() {
     this.input.focus()
   }
@@ -258,7 +273,7 @@ class MaskedInput extends React.Component {
     let eventHandlers = this._getEventHandlers()
     let { size = maxLength, placeholder = this.mask.emptyValue } = this.props
 
-    let { placeholderChar, formatCharacters, ...cleanedProps } = this.props // eslint-disable-line no-unused-vars
+    let { placeholderChar, formatCharacters, onBadInput, ...cleanedProps } = this.props // eslint-disable-line no-unused-vars
     let inputProps = { ...cleanedProps, ...eventHandlers, ref, maxLength, value, size, placeholder }
     return <input {...inputProps} />
   }