diff --git a/pom.xml b/pom.xml
index 3c07b76dd1..e7b367d586 100644
--- a/pom.xml
+++ b/pom.xml
@@ -143,7 +143,7 @@
         <webdriver.version>4.3.1</webdriver.version>
         <wiremock.version>2.27.2</wiremock.version>
         <xml-resolver.version>1.2</xml-resolver.version>
-        <xstream.version>1.4.5</xstream.version> <!-- do not update necessary for lesson -->
+        <xstream.version>1.4.21</xstream.version> <!-- do not update necessary for lesson -->
         <zxcvbn.version>1.5.2</zxcvbn.version>
     </properties>