diff --git a/src/main/java/info/magnolia/cms/security/auth/callback/CASClientCallback.java b/src/main/java/info/magnolia/cms/security/auth/callback/CASClientCallback.java
index 850c444..687e3c9 100644
--- a/src/main/java/info/magnolia/cms/security/auth/callback/CASClientCallback.java
+++ b/src/main/java/info/magnolia/cms/security/auth/callback/CASClientCallback.java
@@ -19,6 +19,7 @@ import info.magnolia.cms.security.cas.CASModule;
 import info.magnolia.module.ModuleRegistry;
 
 import java.io.IOException;
+import java.text.MessageFormat;
 
 import javax.inject.Inject;
 import javax.servlet.http.HttpServletRequest;
@@ -102,10 +103,7 @@ public class CASClientCallback extends AbstractHttpClientCallback {
      * @return CAS server logout URL
      */
     private String createLogoutURL() {
-        final StringBuilder casLogoutString = new StringBuilder();
-        casLogoutString.append(moduleConfig.getCasLogoutURL());
-
-        return casLogoutString.toString();
+        return MessageFormat.format(moduleConfig.getCasLogoutURL(), moduleConfig.getCasServiceURL());
     }
 
 }