diff --git a/smx509/parser.go b/smx509/parser.go
index bac32c8..58f24b8 100644
--- a/smx509/parser.go
+++ b/smx509/parser.go
@@ -362,7 +362,7 @@ func parseBasicConstraintsExtension(der cryptobyte.String) (bool, int, error) {
 		}
 	}
 	maxPathLen := -1
-	if !der.Empty() && der.PeekASN1Tag(cryptobyte_asn1.INTEGER) {
+	if der.PeekASN1Tag(cryptobyte_asn1.INTEGER) {
 		if !der.ReadASN1Integer(&maxPathLen) {
 			return false, 0, errors.New("x509: invalid basic constraints c")
 		}