diff --git a/pki/util.go b/pki/util.go
index b052ff80c..9f093af4a 100644
--- a/pki/util.go
+++ b/pki/util.go
@@ -506,8 +506,8 @@ func DeepEqualIPsAltNames(oldIPs, newIPs []net.IP) bool {
 	if len(oldIPs) != len(newIPs) {
 		return false
 	}
-	oldIPsStrings := make([]string, len(oldIPs))
-	newIPsStrings := make([]string, len(newIPs))
+	oldIPsStrings := make([]string, 0, len(oldIPs))
+	newIPsStrings := make([]string, 0, len(newIPs))
 	for i := range oldIPs {
 		oldIPsStrings = append(oldIPsStrings, oldIPs[i].String())
 		newIPsStrings = append(newIPsStrings, newIPs[i].String())