diff --git a/store/src/java/com/zimbra/cs/service/formatter/NativeFormatter.java b/store/src/java/com/zimbra/cs/service/formatter/NativeFormatter.java
index d2ed1ca7329..cb2c1e51d03 100644
--- a/store/src/java/com/zimbra/cs/service/formatter/NativeFormatter.java
+++ b/store/src/java/com/zimbra/cs/service/formatter/NativeFormatter.java
@@ -461,6 +461,7 @@ private static void sendbackOriginalDoc(InputStream is, String contentType, Stri
         }
         // defang when the html and svg attachment was requested with disposition inline
         if (disp.equals(Part.INLINE) && isScriptableContent(contentType)) {
+            contentType = Mime.getContentType(contentType).toLowerCase();
             BrowserDefang defanger = DefangFactory.getDefanger(contentType);
             String content = defanger.defang(Mime.getTextReader(is, contentType, defaultCharset), true);
             resp.setContentType(contentType);
@@ -616,10 +617,7 @@ public static void sendbackBinaryData(HttpServletRequest req, HttpServletRespons
         }
         PushbackInputStream pis = new PushbackInputStream(in, READ_AHEAD_BUFFER_SIZE);
         boolean isSafe = false;
-        HttpUtil.Browser browser = HttpUtil.guessBrowser(req);
-        if (browser != HttpUtil.Browser.IE) {
-            isSafe = true;
-        } else if (disposition.equals(Part.ATTACHMENT)) {
+        if (Part.ATTACHMENT.equals(disposition)) {
             isSafe = true;
             if (isScriptableContent(contentType)) {
                 resp.addHeader("X-Download-Options", "noopen"); // ask it to save the file