diff --git a/libgfortran/ChangeLog b/libgfortran/ChangeLog
index 6940f790b5c9..251e6b4c462c 100644
--- a/libgfortran/ChangeLog
+++ b/libgfortran/ChangeLog
@@ -1,3 +1,9 @@
+2017-11-28  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
+
+	PR libgfortran/83168
+	* io/write.c (select_string): Bump size by one to avoid 
+	overrun.
+
 2017-11-24  Janne Blomqvist  <jb@gcc.gnu.org>
 
 	PR fortran/36313
diff --git a/libgfortran/io/write.c b/libgfortran/io/write.c
index f4172029c0ed..582d196c4e30 100644
--- a/libgfortran/io/write.c
+++ b/libgfortran/io/write.c
@@ -1552,7 +1552,7 @@ select_string (st_parameter_dt *dtp, const fnode *f, char *buf, size_t *size,
 	       int kind)
 {
   char *result;
-  *size = size_from_kind (dtp, f, kind) + f->u.real.d;
+  *size = size_from_kind (dtp, f, kind) + f->u.real.d + 1;
   if (*size > BUF_STACK_SZ)
      result = xmalloc (*size);
   else