🔒️ fix CVE-2019-11358

Author: ctcpip

src/core.js

@@ -156,8 +156,9 @@ jQuery.extend = jQuery.fn.extend = function() {
 				src = target[ name ];
 				copy = options[ name ];
 
+				// Prevent Object.prototype pollution
 				// Prevent never-ending loop
-				if ( target === copy ) {
+				if ( name === "__proto__" || target === copy ) {
 					continue;
 				}
 

test/unit/core.js

@@ -1228,6 +1228,13 @@ QUnit.test( "jQuery.extend(true,{},{a:[], o:{}}); deep copy with array, followed
 	assert.ok( !jQuery.isArray( result.object ), "result.object wasn't paved with an empty array" );
 } );
 
+QUnit.test( "jQuery.extend( true, ... ) Object.prototype pollution", function( assert ) {
+	assert.expect( 1 );
+
+	jQuery.extend( true, {}, JSON.parse( "{\"__proto__\": {\"devMode\": true}}" ) );
+	assert.ok( !( "devMode" in {} ), "Object.prototype not polluted" );
+} );
+
 QUnit.test( "jQuery.each(Object,Function)", function( assert ) {
 	assert.expect( 23 );