diff --git a/bin/cli.js b/bin/cli.js
index 970de72351..d9dec51352 100755
--- a/bin/cli.js
+++ b/bin/cli.js
@@ -144,7 +144,7 @@ async function run () {
 
   process.on('SIGINT', async () => {
     logger.info('Caught interrupt signal. Shutting down...')
-    if (server) await server.stop()
+    if (server) server.http().close()
     await node.stop()
     logger.info('Exiting.')
     process.exit()
diff --git a/lib/rpc/validation.js b/lib/rpc/validation.js
index 2b71e3696e..5075a61857 100644
--- a/lib/rpc/validation.js
+++ b/lib/rpc/validation.js
@@ -43,6 +43,13 @@ module.exports = {
      */
     hex (params, index) {
       let err
+      if (typeof params[index] !== 'string') {
+        return {
+          code: INVALID_PARAMS,
+          message: `invalid argument ${index}: argument must be a hex string`
+        }
+      }
+
       if (params[index].substr(0, 2) !== '0x') {
         err = {
           code: INVALID_PARAMS,
@@ -60,6 +67,14 @@ module.exports = {
      */
     blockHash (params, index) {
       let err
+
+      if (typeof params[index] !== 'string') {
+        return {
+          code: INVALID_PARAMS,
+          message: `invalid argument ${index}: argument must be a hex string`
+        }
+      }
+
       let blockHash = params[index].substring(2)
 
       if (!/^[0-9a-fA-F]+$/.test(blockHash) | blockHash.length !== 64) {