Index: /CKEditor/trunk/CHANGES.html
===================================================================
--- /CKEditor/trunk/CHANGES.html	(revision 5739)
+++ /CKEditor/trunk/CHANGES.html	(revision 5740)
@@ -89,4 +89,5 @@
 		<li><a href="http://dev.fckeditor.net/ticket/5634">#5634</a> : IE: It was needed to click twice in the editor to make it editable on some situations.</li>
 		<li><a href="http://dev.fckeditor.net/ticket/5338">#5338</a> : Pasting from Open Office could lead on error.</li>
+		<li><a href="http://dev.fckeditor.net/ticket/5224">#5224</a> : Some invalid markup could break the editor.</li>
 		<li>Updated the following language files:<ul>
 			<li><a href="http://dev.fckeditor.net/ticket/5962">#5962</a> : German;</li>
Index: /CKEditor/trunk/_source/core/htmlparser.js
===================================================================
--- /CKEditor/trunk/_source/core/htmlparser.js	(revision 5739)
+++ /CKEditor/trunk/_source/core/htmlparser.js	(revision 5740)
@@ -173,4 +173,10 @@
 				{
 					tagName = tagName.toLowerCase();
+
+					// There are some tag names that can break things, so let's
+					// simply ignore them when parsing. (#5224)
+					if ( /="/.test( tagName ) )
+						continue;
+
 					var attribs = {},
 						attribMatch,