diff --git a/lib/script/script.js b/lib/script/script.js
index 3f25faa..544471d 100644
--- a/lib/script/script.js
+++ b/lib/script/script.js
@@ -255,6 +255,7 @@ Script.prototype.isPublicKeyHashIn = function(inaccurate) {
     if (signatureBuf &&
         signatureBuf.length &&
         signatureBuf[0] === 0x30 &&
+        pubkeyBuf &&
         pubkeyBuf.length
        ) {
       var version = pubkeyBuf[0];