Index: src/wp-admin/includes/class-wp-automatic-updater.php
===================================================================
--- src/wp-admin/includes/class-wp-automatic-updater.php	(revision 51877)
+++ src/wp-admin/includes/class-wp-automatic-updater.php	(working copy)
@@ -55,6 +55,24 @@
 		return apply_filters( 'automatic_updater_disabled', $disabled );
 	}
 
+	public function is_allowed_dir( $dir ) {
+		$open_basedir = ini_get('open_basedir');
+
+		if ( !$open_basedir ) {
+			return true;
+		}
+
+		$open_basedir_dirs = explode(PATH_SEPARATOR, $open_basedir);
+
+		foreach ( $open_basedir_dirs as $basedir ) {
+			if ( strpos( $dir, $basedir ) === 0 ) {
+				return true;
+			}
+		}
+
+		return false;
+}
+
 	/**
 	 * Check for version control checkouts.
 	 *
@@ -101,7 +119,7 @@
 		// Search all directories we've found for evidence of version control.
 		foreach ( $vcs_dirs as $vcs_dir ) {
 			foreach ( $check_dirs as $check_dir ) {
-				$checkout = @is_dir( rtrim( $check_dir, '\\/' ) . "/$vcs_dir" );
+				$checkout = $this->is_allowed_dir( $check_dir ) && @is_dir( rtrim( $check_dir, '\\/' ) . "/$vcs_dir" );
 				if ( $checkout ) {
 					break 2;
 				}