fix: Added an experimental fix for an mXSS detection regex

Author: cure53

dist/purify.cjs.js

@@ -901,7 +901,7 @@ function createDOMPurify() {
       allowedTags: ALLOWED_TAGS
     });
     /* Detect mXSS attempts abusing namespace confusion */
-    if (currentNode.hasChildNodes() && !_isNode(currentNode.firstElementChild) && regExpTest(/<[/\w]/g, currentNode.innerHTML) && regExpTest(/<[/\w]/g, currentNode.textContent)) {
+    if (currentNode.hasChildNodes() && !_isNode(currentNode.firstElementChild) && regExpTest(/<[/\w!]/g, currentNode.innerHTML) && regExpTest(/<[/\w!]/g, currentNode.textContent)) {
       _forceRemove(currentNode);
       return true;
     }