diff --git a/Library/Homebrew/cask/installer.rb b/Library/Homebrew/cask/installer.rb
index 20609203fb..b8129e125a 100644
--- a/Library/Homebrew/cask/installer.rb
+++ b/Library/Homebrew/cask/installer.rb
@@ -175,6 +175,8 @@ module Cask
           tmpdir = Pathname(tmpdir)
           primary_container.extract(to: tmpdir, basename: basename, verbose: verbose?)
 
+          FileUtils.chmod_R "+rw", tmpdir/nested_container, force: true, verbose: verbose?
+
           UnpackStrategy.detect(tmpdir/nested_container)
                         .extract_nestedly(to: @cask.staged_path, verbose: verbose?)
         end