diff --git a/tool/lib/bundled_gem.rb b/tool/lib/bundled_gem.rb
index 3ba27f6d64..8730f0fb3a 100644
--- a/tool/lib/bundled_gem.rb
+++ b/tool/lib/bundled_gem.rb
@@ -11,7 +11,8 @@ module BundledGem
     "time", # net-ftp
     "singleton", # prime
     "ipaddr", # rinda
-    "forwardable" # prime, rinda
+    "forwardable", # prime, rinda
+    "strscan" # rexml
   ]
 
   module_function