diff --git a/Gemfile.lock b/Gemfile.lock
index c4f06c6..be9a048 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -12,7 +12,7 @@ GEM
     colored (1.2)
     ethon (0.8.1)
       ffi (>= 1.3.0)
-    ffi (1.9.10)
+    ffi (1.15.5)
     html-proofer (2.6.4)
       activesupport (~> 4.2)
       addressable (~> 2.3)