diff --git a/core/lib/Drupal/Component/PhpStorage/FileStorage.php b/core/lib/Drupal/Component/PhpStorage/FileStorage.php
index d588af4..5f23cad 100644
--- a/core/lib/Drupal/Component/PhpStorage/FileStorage.php
+++ b/core/lib/Drupal/Component/PhpStorage/FileStorage.php
@@ -109,7 +109,7 @@ class FileStorage implements PhpStorageInterface {
   protected function unlink($path) {
     if (file_exists($path)) {
       // Ensure the file / folder is writable.
-      chmod($path, 0700);
+      chmod($path, 0777 & ~umask());
       if (is_dir($path)) {
         $dir = dir($path);
         while (($entry = $dir->read()) !== FALSE) {
diff --git a/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php b/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php
index 4d564fb..7febbc7 100644
--- a/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php
+++ b/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php
@@ -81,7 +81,7 @@ class MTimeProtectedFastFileStorage extends FileStorage {
     if (!@file_put_contents($temporary_path, $data)) {
       return FALSE;
     }
-    chmod($temporary_path, 0400);
+    chmod($temporary_path, 0444  & ~umask());
 
     // Prepare a directory dedicated for just this file. Ensure it has a current
     // mtime so that when the file (hashed on that mtime) is moved into it, the
@@ -107,7 +107,7 @@ class MTimeProtectedFastFileStorage extends FileStorage {
     $i = 0;
     while (($mtime = $this->getUncachedMTime($directory)) && ($mtime != $previous_mtime)) {
       $previous_mtime = $mtime;
-      chmod($directory, 0700);
+      chmod($directory, 0777 & ~umask());
       // Reset the file back in the temporary location if this is not the first
       // iteration.
       if ($i > 0) {
@@ -124,7 +124,7 @@ class MTimeProtectedFastFileStorage extends FileStorage {
       // Leave the directory neither readable nor writable. Since the file
       // itself is not writable (set to 0400 at the beginning of this function),
       // there's no way to tamper with it without access to change permissions.
-      chmod($directory, 0100);
+      chmod($directory, 0111 & ~umask());
       $i++;
     }
     return TRUE;
@@ -147,12 +147,12 @@ class MTimeProtectedFastFileStorage extends FileStorage {
    */
   protected function ensureDirectory() {
     if (!file_exists($this->directory)) {
-      mkdir($this->directory, 0700, TRUE);
+      mkdir($this->directory, 0777 & ~umask(), TRUE);
     }
-    chmod($this->directory, 0700);
+    chmod($this->directory, 0777 & ~umask());
     $htaccess_path =  $this->directory . '/.htaccess';
     if (!file_exists($htaccess_path) && file_put_contents($htaccess_path, self::HTACCESS)) {
-      @chmod($htaccess_path, 0444);
+      @chmod($htaccess_path, 0444 & ~umask());
     }
   }
 
@@ -163,7 +163,7 @@ class MTimeProtectedFastFileStorage extends FileStorage {
    *   The directory to be emptied out.
    */
   protected function cleanDirectory($directory) {
-    chmod($directory, 0700);
+    chmod($directory, 0777 & ~umask());
     foreach (new DirectoryIterator($directory) as $fileinfo) {
       if (!$fileinfo->isDot()) {
         $this->unlink($fileinfo->getPathName());
diff --git a/core/modules/system/lib/Drupal/system/Tests/PhpStorage/MTimeProtectedFileStorageTest.php b/core/modules/system/lib/Drupal/system/Tests/PhpStorage/MTimeProtectedFileStorageTest.php
index ae54c2f..d9a7d76 100644
--- a/core/modules/system/lib/Drupal/system/Tests/PhpStorage/MTimeProtectedFileStorageTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/PhpStorage/MTimeProtectedFileStorageTest.php
@@ -71,8 +71,8 @@ function testSecurity() {
     // minimal permissions. fileperms() can return high bits unrelated to
     // permissions, so mask with 0777.
     $this->assertTrue(file_exists($expected_filename));
-    $this->assertIdentical(fileperms($expected_filename) & 0777, 0400);
-    $this->assertIdentical(fileperms($expected_directory) & 0777, 0100);
+    $this->assertIdentical(fileperms($expected_filename) & 0777, 0444 & ~umask());
+    $this->assertIdentical(fileperms($expected_directory) & 0777, 0111 & ~umask());
 
     // Ensure the root directory for the bin has a .htaccess file denying web
     // access.
@@ -88,8 +88,8 @@ function testSecurity() {
       $php = $this->storageFactory->get('simpletest');
       $GLOBALS['hacked'] = FALSE;
       $untrusted_code = "<?php\n" . '$GLOBALS["hacked"] = TRUE;';
-      chmod($expected_directory, 0700);
-      chmod($expected_filename, 0700);
+      chmod($expected_directory, 0777 & ~umask());
+      chmod($expected_filename, 0777 & ~umask());
       if ($i) {
         // Now try to write the file in such a way that the directory mtime
         // changes and invalidates the hash.
@@ -101,8 +101,8 @@ function testSecurity() {
         // is now larger than the directory mtime.
         file_put_contents($expected_filename, $untrusted_code);
       }
-      chmod($expected_filename, 0400);
-      chmod($expected_directory, 0100);
+      chmod($expected_filename, 0444 & ~umask());
+      chmod($expected_directory, 0111 & ~umask());
       $this->assertIdentical(file_get_contents($expected_filename), $untrusted_code);
       $this->assertIdentical($php->exists($name), $this->expected[$i]);
       $this->assertIdentical($php->load($name), $this->expected[$i]);