diff --git a/mozilla/content/base/src/nsImageLoadingContent.cpp b/mozilla/content/base/src/nsImageLoadingContent.cpp
index 4951a099320..d7e6964e1b6 100644
--- a/mozilla/content/base/src/nsImageLoadingContent.cpp
+++ b/mozilla/content/base/src/nsImageLoadingContent.cpp
@@ -376,8 +376,12 @@ nsImageLoadingContent::GetCurrentURI(nsIURI** aURI)
     return mCurrentRequest->GetURI(aURI);
   }
 
-  NS_IF_ADDREF(*aURI = mCurrentURI);
-  return NS_OK;
+  if (!mCurrentURI) {
+    *aURI = nsnull;
+    return NS_OK;
+  }
+  
+  return NS_EnsureSafeToReturn(mCurrentURI, aURI);
 }
 
 NS_IMETHODIMP
@@ -445,6 +449,8 @@ nsImageLoadingContent::LoadImage(const nsAString& aNewURI,
   NS_ENSURE_SUCCESS(rv, rv);
   // XXXbiesi fire onerror if that failed?
 
+  NS_TryToSetImmutable(imageURI);
+
   return LoadImage(imageURI, aForce, aNotify, doc);
 }
 
diff --git a/mozilla/content/base/src/nsObjectLoadingContent.cpp b/mozilla/content/base/src/nsObjectLoadingContent.cpp
index 3f92b07c330..72afd9e5237 100644
--- a/mozilla/content/base/src/nsObjectLoadingContent.cpp
+++ b/mozilla/content/base/src/nsObjectLoadingContent.cpp
@@ -705,6 +705,8 @@ nsObjectLoadingContent::LoadObject(const nsAString& aURI,
     return NS_OK;
   }
 
+  NS_TryToSetImmutable(uri);
+
   return LoadObject(uri, aNotify, aTypeHint, aForceLoad);
 }