diff --git a/src/rocksdb2/docs/Gemfile.lock b/src/rocksdb2/docs/Gemfile.lock
index 346fc6c1e..1ab06c052 100644
--- a/src/rocksdb2/docs/Gemfile.lock
+++ b/src/rocksdb2/docs/Gemfile.lock
@@ -18,7 +18,7 @@ GEM
     execjs (2.7.0)
     faraday (0.9.2)
       multipart-post (>= 1.2, < 3)
-    ffi (1.9.14)
+    ffi (1.13.1)
     forwardable-extended (2.6.0)
     gemoji (2.1.0)
     github-pages (104)