diff --git a/ssl/handshake_server.cc b/ssl/handshake_server.cc
index 5f2f41f..7ade8fc 100644
--- a/ssl/handshake_server.cc
+++ b/ssl/handshake_server.cc
@@ -334,7 +334,7 @@
     SSL_HANDSHAKE *hs, const SSL_CLIENT_HELLO *client_hello,
     const struct ssl_cipher_preference_list_st *server_pref) {
   SSL *const ssl = hs->ssl;
-  STACK_OF(SSL_CIPHER) *prio, *allow;
+  const STACK_OF(SSL_CIPHER) *prio, *allow;
   // in_group_flags will either be NULL, or will point to an array of bytes
   // which indicate equal-preference groups in the |prio| stack. See the
   // comment about |in_group_flags| in the |ssl_cipher_preference_list_st|