diff --git a/apps/app_queue.c b/apps/app_queue.c
index de06df8619..da99ab0a31 100644
--- a/apps/app_queue.c
+++ b/apps/app_queue.c
@@ -4381,7 +4381,7 @@ static int manager_add_queue_member(struct mansession *s, const struct message *
 
 	if (ast_strlen_zero(penalty_s))
 		penalty = 0;
-	else if (sscanf(penalty_s, "%d", &penalty) != 1)
+	else if (sscanf(penalty_s, "%d", &penalty) != 1 || penalty < 0)
 		penalty = 0;
 
 	if (ast_strlen_zero(paused_s))