diff -pruN uim-1.8.6.orig/uim/m17nlib.c uim-1.8.6/uim/m17nlib.c
--- uim-1.8.6.orig/uim/m17nlib.c	2013-06-30 13:26:09.000000000 +0900
+++ uim-1.8.6/uim/m17nlib.c	2018-02-27 20:01:51.098951178 +0900
@@ -232,7 +232,7 @@ static char *
 convert_mtext2str(MText *mtext)
 {
   mconv_rebind_buffer(converter, (unsigned char *)buffer_for_converter,
-		      sizeof(buffer_for_converter));
+		      sizeof(buffer_for_converter)-1);
   mconv_encode(converter, mtext);
   buffer_for_converter[converter->nbytes] = 0;