diff --git a/CHANGES b/CHANGES
index 4665120efde1e61173dc011db58850b6833d66b2..3a0d678ed51e10674712d75cab4209b0ad6a6eda 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3,6 +3,9 @@
 
  Changes between 0.9.6 and 0.9.7  [xx XXX 2000]
 
+  *) Make sk_sort() tolerate a NULL argument.
+     [Steve Henson reported by Massimiliano Pala <madwolf@comune.modena.it>]
+
   *) New OCSP verify flag OCSP_TRUSTOTHER. When set the "other" certificates
      passed by the function are trusted implicitly. If any of them signed the
      reponse then it is assumed to be valid and is not verified.
diff --git a/crypto/stack/stack.c b/crypto/stack/stack.c
index 02857f044664bf4ee34c21a6514855f9ee1ec718..9a75e433d711647447a26b8038c9fe1bbe186b0b 100644
--- a/crypto/stack/stack.c
+++ b/crypto/stack/stack.c
@@ -316,7 +316,7 @@ char *sk_set(STACK *st, int i, char *value)
 
 void sk_sort(STACK *st)
 	{
-	if (!st->sorted)
+	if (st && !st->sorted)
 		{
 		int (*comp_func)(const void *,const void *);