diff --git a/components/engine/docs/security/security.md b/components/engine/docs/security/security.md
index 44853c22bb..7ab127cb5a 100644
--- a/components/engine/docs/security/security.md
+++ b/components/engine/docs/security/security.md
@@ -12,7 +12,7 @@ weight =-99
 
 # Docker security
 
-There are three major areas to consider when reviewing Docker security:
+There are four major areas to consider when reviewing Docker security:
 
  - the intrinsic security of the kernel and its support for
    namespaces and cgroups;