diff --git a/var/spack/repos/builtin/packages/ncl/package.py b/var/spack/repos/builtin/packages/ncl/package.py
index 49ebbc8f47..1d338bcd9c 100644
--- a/var/spack/repos/builtin/packages/ncl/package.py
+++ b/var/spack/repos/builtin/packages/ncl/package.py
@@ -43,6 +43,8 @@ class Ncl(Package):
     patch('spack_ncl.patch')
     # Make ncl compile with hdf5 1.10
     patch('hdf5.patch')
+    # ymake-filter's buffer may overflow
+    patch('ymake-filter.patch')
 
     # This installation script is implemented according to this manual:
     # http://www.ncl.ucar.edu/Download/build_from_src.shtml
diff --git a/var/spack/repos/builtin/packages/ncl/ymake-filter.patch b/var/spack/repos/builtin/packages/ncl/ymake-filter.patch
new file mode 100644
index 0000000000..915e82035f
--- /dev/null
+++ b/var/spack/repos/builtin/packages/ncl/ymake-filter.patch
@@ -0,0 +1,33 @@
+--- ncl_ncarg-6.4.0/config/ymake-filter.c.orig	2017-02-23 20:11:55.000000000 +0100
++++ ncl_ncarg-6.4.0/config/ymake-filter.c	2017-09-13 14:52:34.800989229 +0200
+@@ -150,13 +150,29 @@
+ getcppline()
+ {
+ 	int		c;
+-	static char	buf[2048];
++	static int	s = 2048;
++	static char	*buf = NULL;
+ 	char 		*p;
+ 
++	if (buf == NULL)
++	{
++		buf = malloc(s);
++	}
++
+ 	p = buf;
+ 
+ 	do
+ 	{
++		if (p >= buf + s)
++		{
++			char* old = buf;
++
++			/* Need to increase the size of buf. */
++			s += 1024;
++			buf = realloc(buf, s);
++			p = buf + (p - old);
++		}
++
+ 		switch(c = getchar())
+ 		{
+ 			/*