diff --git a/fluent-plugin-events/Gemfile.lock b/fluent-plugin-events/Gemfile.lock
index 477d99d..5ac8f2b 100644
--- a/fluent-plugin-events/Gemfile.lock
+++ b/fluent-plugin-events/Gemfile.lock
@@ -92,12 +92,14 @@ GEM
     public_suffix (5.0.4)
     rake (13.2.1)
     recursive-open-struct (1.1.3)
-    rexml (3.2.6)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     ruby2_keywords (0.0.5)
     serverengine (2.3.2)
       sigdump (~> 0.2.2)
     sigdump (0.2.5)
     strptime (0.2.5)
+    strscan (3.1.0)
     test-unit (3.6.2)
       power_assert
     tzinfo (2.0.4)