diff --git a/pom.xml b/pom.xml
index 7063e64..a125191 100644
--- a/pom.xml
+++ b/pom.xml
@@ -60,7 +60,7 @@
                     <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>