diff --git a/pom.xml b/pom.xml
index e78dce1..c2c44f4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -9,7 +9,7 @@
   <version>2.0.0</version>
   <url>https://www.commonwl.org/</url>
   <properties>
-    <commonslang.version>3.20.0</commonslang.version>
+    <commonslang.version>3.21.0</commonslang.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
   </properties>