diff --git a/pom.xml b/pom.xml
index 83f7374d..da3aea3c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -349,7 +349,7 @@
           <dependency>
             <groupId>com.thoughtworks.xstream</groupId>
             <artifactId>xstream</artifactId>
-            <version>1.4.15</version> <!-- apparently this needs to be exactly this version -->
+            <version>1.4.21</version> <!-- apparently this needs to be exactly this version -->
           </dependency>
         </dependencies>
       </plugin>