diff --git a/vncviewer/CConn.cxx b/vncviewer/CConn.cxx
index 4aeb03f..f97b0f4 100644
--- a/vncviewer/CConn.cxx
+++ b/vncviewer/CConn.cxx
@@ -364,7 +364,7 @@
   ret = fl_utf8froma(buffer, size, str, len);
   assert(ret < size);
 
-  vlog.debug("Got clipboard data: '%s'", buffer);
+  vlog.debug("Got clipboard data (%d bytes)", strlen(buffer));
 
   // RFB doesn't have separate selection and clipboard concepts, so we
   // dump the data into both variants.
diff --git a/vncviewer/Viewport.cxx b/vncviewer/Viewport.cxx
index 9fd849f..4b8a85b 100644
--- a/vncviewer/Viewport.cxx
+++ b/vncviewer/Viewport.cxx
@@ -365,7 +365,7 @@
                      Fl::event_length() + 1);
     assert(ret < (Fl::event_length() + 1));
 
-    vlog.debug("Sending clipboard data: '%s'", buffer);
+    vlog.debug("Sending clipboard data (%d bytes)", strlen(buffer));
 
     try {
       cc->writer()->clientCutText(buffer, ret);