diff --git a/thingifier/pom.xml b/thingifier/pom.xml
index 2b1bb5f6..1a7febc0 100644
--- a/thingifier/pom.xml
+++ b/thingifier/pom.xml
@@ -48,7 +48,7 @@
       <dependency>
           <groupId>com.thoughtworks.xstream</groupId>
           <artifactId>xstream</artifactId>
-          <version>1.4.19</version>
+          <version>1.4.21</version>
       </dependency>
       <dependency>
           <groupId>com.sparkjava</groupId>