diff --git a/wp-admin/includes/file.php b/wp-admin/includes/file.php
index e527b2eb97..5abb4cfba5 100644
--- a/wp-admin/includes/file.php
+++ b/wp-admin/includes/file.php
@@ -643,10 +643,13 @@ function _unzip_file_ziparchive($file, $to, $needed_dirs = array() ) {
 
 		$uncompressed_size += $info['size'];
 
-		if ( '/' == substr($info['name'], -1) ) // directory
-			$needed_dirs[] = $to . untrailingslashit($info['name']);
-		else
-			$needed_dirs[] = $to . untrailingslashit(dirname($info['name']));
+		if ( '/' === substr( $info['name'], -1 ) ) {
+			// Directory.
+			$needed_dirs[] = $to . untrailingslashit( $info['name'] );
+		} elseif ( '.' !== $dirname = dirname( $info['name'] ) ) {
+			// Path to a file.
+			$needed_dirs[] = $to . untrailingslashit( $dirname );
+		}
 	}
 
 	/*
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 5a29078b40..a8b95baf3b 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-alpha-37419';
+$wp_version = '4.6-alpha-37421';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.