Index: applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSGrabber.java
===================================================================
--- applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSGrabber.java	(revision 19626)
+++ applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSGrabber.java	(revision 20566)
@@ -210,5 +210,6 @@
         String line = null;
         while( (line = br.readLine()) != null) {
-            exception.append(line);
+            // filter non-ASCII characters and control characters
+            exception.append(line.replaceAll("[^\\p{Print}]", ""));
             exception.append('\n');
         }