Merged 7.78.

CHANGELOG.txt

@@ -1,6 +1,11 @@
 Drupal 7.xx, xxxx-xx-xx (development version)
 -----------------------
 
+Drupal 7.78, 2021-01-19
+-----------------------
+- Fixed security issues:
+   - SA-CORE-2021-001
+
 Drupal 7.77, 2020-12-03
 -----------------------
 - Hotfix for schema.prefixed tables

modules/system/system.tar.inc

@@ -2178,6 +2178,14 @@ class Archive_Tar
                             }
                         }
                     } elseif ($v_header['typeflag'] == "2") {
+                        if (strpos(realpath(dirname($v_header['link'])), realpath($p_path)) !== 0) {
+                            $this->_error(
+                                'Out-of-path file extraction {'
+                                . $v_header['filename'] . ' --> ' .
+                                $v_header['link'] . '}'
+                            );
+                            return false;
+                        }
                         if (!$p_symlinks) {
                             $this->_warning('Symbolic links are not allowed. '
                                 . 'Unable to extract {'