--- a/toolkit/components/feeds/FeedProcessor.js
+++ b/toolkit/components/feeds/FeedProcessor.js
@@ -620,17 +620,18 @@ TextConstruct.prototype = {
     var isXML;
     if (this.type == "xhtml")
       isXML = true
     else if (this.type == "html")
       isXML = false;
     else
       return null;
 
-    return this.parserUtils.parseFragment(this.text, 0, isXML,
+    let flags = Ci.nsIParserUtils.SanitizerDropForms;
+    return this.parserUtils.parseFragment(this.text, flags, isXML,
                                           this.base, element);
   },
 
   // XPCOM stuff
   classID: TEXTCONSTRUCT_CLASSID,
   QueryInterface: XPCOMUtils.generateQI([Ci.nsIFeedTextConstruct])
 }