diff --git a/validator/validator.c b/validator/validator.c
index e83948492..6cd15cfc1 100644
--- a/validator/validator.c
+++ b/validator/validator.c
@@ -204,7 +204,7 @@ val_init(struct module_env* env, int id)
 		struct trust_anchor* anchor = anchors_find_any_noninsecure(
 			env->anchors);
 		if(anchor) {
-			char b[257];
+			char b[LDNS_MAX_DOMAINLEN+2];
 			dname_str(anchor->name, b);
 			log_warn("validator: disable-edns-do is enabled, but there is a trust anchor for '%s'. Since DNSSEC could not work, the disable-edns-do setting is turned off. Continuing without it.", b);
 			lock_basic_unlock(&anchor->lock);