diff --git a/lib/webpack/server.config.js b/lib/webpack/server.config.js
index aac5e7b754..3a811d3cf2 100644
--- a/lib/webpack/server.config.js
+++ b/lib/webpack/server.config.js
@@ -61,6 +61,7 @@ export default function () {
       config.externals = config.externals.concat(Object.keys(projectPackageJson.dependencies || {}))
     } catch (e) {}
   }
+  config.externals = config.externals.concat(this.options.build.vendor)
   config.externals = uniq(config.externals)
 
   // Extend config