diff --git a/etc/inc/captiveportal.inc b/etc/inc/captiveportal.inc
index b0cbf14845..cd419ff54b 100644
--- a/etc/inc/captiveportal.inc
+++ b/etc/inc/captiveportal.inc
@@ -697,7 +697,7 @@ function captiveportal_prune_old() {
 		}
 
 		/* if vouchers are configured, activate session timeouts */
-		if (!$timedout && isset($config['voucher']['enable'])) {
+		if (!$timedout && isset($config['voucher']['enable']) && !empty($cpentry[7])) {
 			if ($pruning_time >= ($cpentry[0] + $cpentry[7])) {
 				$timedout = true;
 				$term_cause = 5; // Session-Timeout