--- a/accessible/atk/nsMaiInterfaceText.cpp
+++ b/accessible/atk/nsMaiInterfaceText.cpp
@@ -458,18 +458,18 @@ getRangeExtentsCB(AtkText *aText, gint a
 }
 
 static gint
 getCharacterCountCB(AtkText *aText)
 {
   AccessibleWrap* accWrap = GetAccessibleWrap(ATK_OBJECT(aText));
   if (accWrap) {
     HyperTextAccessible* textAcc = accWrap->AsHyperText();
-    return
-      textAcc->IsDefunct() ? 0 : static_cast<gint>(textAcc->CharacterCount());
+    return !textAcc || textAcc->IsDefunct() ?
+        0 : static_cast<gint>(textAcc->CharacterCount());
   }
 
   if (ProxyAccessible* proxy = GetProxy(ATK_OBJECT(aText))) {
     return proxy->CharacterCount();
   }
 
   return 0;
 }