diff --git a/lib/rubygems/package.rb b/lib/rubygems/package.rb
index 387e40ffd753bb..72a179da376d87 100644
--- a/lib/rubygems/package.rb
+++ b/lib/rubygems/package.rb
@@ -454,7 +454,7 @@ def extract_tar_gz(io, destination_dir, pattern = "*") # :nodoc:
 
         if entry.file?
           File.open(destination, "wb") {|out| copy_stream(entry, out) }
-          FileUtils.chmod file_mode(entry.header.mode), destination
+          FileUtils.chmod file_mode(entry.header.mode) & ~File.umask, destination
         end
 
         verbose destination
diff --git a/test/rubygems/test_gem.rb b/test/rubygems/test_gem.rb
index d4c307978e7c5d..244b7749a5ead1 100644
--- a/test/rubygems/test_gem.rb
+++ b/test/rubygems/test_gem.rb
@@ -133,7 +133,7 @@ def test_self_install_permissions_umask_0
 
   def test_self_install_permissions_umask_077
     umask = File.umask(0o077)
-    assert_self_install_permissions
+    assert_self_install_permissions(data_mode: 0o600)
   ensure
     File.umask(umask)
   end
@@ -151,12 +151,12 @@ def test_self_install_permissions_with_format_executable_and_non_standard_ruby_i
     Gem::Installer.exec_format = nil
   end
 
-  def assert_self_install_permissions(format_executable: false)
+  def assert_self_install_permissions(format_executable: false, data_mode: 0o640)
     mask = Gem.win_platform? ? 0o700 : 0o777
     options = {
       dir_mode: 0o500,
       prog_mode: Gem.win_platform? ? 0o410 : 0o510,
-      data_mode: 0o640,
+      data_mode: data_mode,
       wrappers: true,
       format_executable: format_executable,
     }