diff --git a/doc/Gemfile.lock b/doc/Gemfile.lock
index a210e5d4c..5f500be25 100644
--- a/doc/Gemfile.lock
+++ b/doc/Gemfile.lock
@@ -237,7 +237,7 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.6)
+    rexml (3.3.9)
     rouge (3.30.0)
     ruby2_keywords (0.0.5)
     rubyzip (2.3.2)