diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c
index 0bd8a61..fef5d2e 100644
--- a/lib/asn1_decoder.c
+++ b/lib/asn1_decoder.c
@@ -284,6 +284,9 @@ int asn1_ber_decoder(const struct asn1_decoder *decoder,
 				if (unlikely(len > datalen - dp))
 					goto data_overrun_error;
 			}
+		} else {
+			if (unlikely(len > datalen - dp))
+				goto data_overrun_error;
 		}
 
 		if (flags & FLAG_CONS) {