diff --git a/ssh/kex.c b/ssh/kex.c
index fda2988..2fd621b 100644
--- a/ssh/kex.c
+++ b/ssh/kex.c
@@ -310,9 +310,42 @@ kex_new(struct ssh *ssh, char *proposal[PROPOSAL_MAX], Kex **kexp)
 	return r;
 }
 
+void
+kex_free_newkeys(Newkeys *newkeys)
+{
+	if (newkeys == NULL)
+		return;
+	if (newkeys->enc.key) {
+		bzero(newkeys->enc.key, newkeys->enc.key_len);
+		free(newkeys->enc.key);
+		newkeys->enc.key = NULL;
+	}
+	if (newkeys->enc.iv) {
+		bzero(newkeys->enc.iv, newkeys->enc.block_size);
+		free(newkeys->enc.iv);
+		newkeys->enc.iv = NULL;
+	}
+	free(newkeys->enc.name);
+	bzero(&newkeys->enc, sizeof(newkeys->enc));
+	free(newkeys->comp.name);
+	bzero(&newkeys->comp, sizeof(newkeys->comp));
+	mac_clear(&newkeys->mac);
+	if (newkeys->mac.key) {
+		bzero(newkeys->mac.key, newkeys->mac.key_len);
+		free(newkeys->mac.key);
+		newkeys->mac.key = NULL;
+	}
+	free(newkeys->mac.name);
+	bzero(&newkeys->mac, sizeof(newkeys->mac));
+	bzero(newkeys, sizeof(*newkeys));
+	free(newkeys);
+}
+
 void
 kex_free(Kex *kex)
 {
+	u_int mode;
+
 	if (kex->peer != NULL)
 		sshbuf_free(kex->peer);
 	if (kex->my != NULL)
@@ -321,6 +354,10 @@ kex_free(Kex *kex)
 		DH_free(kex->dh);
 	if (kex->ec_client_key)
 		EC_KEY_free(kex->ec_client_key);
+	for (mode = 0; mode < MODE_MAX; mode++) {
+		kex_free_newkeys(kex->newkeys[mode]);
+		kex->newkeys[mode] = NULL;
+	}
 	free(kex);
 }
 
@@ -610,7 +647,7 @@ derive_key(struct ssh *ssh, int id, u_int need, u_char *hash, u_int hashlen,
 	r = 0;
  out:
 	if (digest)
-		free (digest);
+		free(digest);
 	if (b)
 		sshbuf_free(b);
 	return r;
@@ -635,6 +672,7 @@ kex_derive_keys(struct ssh *ssh, u_char *hash, u_int hashlen,
 		}
 	}
 	for (mode = 0; mode < MODE_MAX; mode++) {
+		kex_free_newkeys(ssh->current_keys[mode]);
 		ssh->current_keys[mode] = kex->newkeys[mode];
 		kex->newkeys[mode] = NULL;
 		ctos = (!kex->server && mode == MODE_OUT) ||
diff --git a/ssh/kex.h b/ssh/kex.h
index 9359219..bb45561 100644
--- a/ssh/kex.h
+++ b/ssh/kex.h
@@ -137,6 +137,7 @@ int	 kex_names_valid(const char *);
 
 int	 kex_new(struct ssh *, char *[PROPOSAL_MAX], Kex **);
 int	 kex_setup(struct ssh *, char *[PROPOSAL_MAX]);
+void	 kex_free_newkeys(Newkeys *);
 void	 kex_free(Kex *);
 
 int	 kex_buf2prop(struct sshbuf *, int *, char ***);
diff --git a/ssh/packet.c b/ssh/packet.c
index 7d6f750..dad87df 100644
--- a/ssh/packet.c
+++ b/ssh/packet.c
@@ -530,6 +530,7 @@ ssh_packet_close(struct ssh *ssh)
 {
 	struct session_state *state = ssh->state;
 	int r;
+	u_int mode;
 
 	if (!state->initialized)
 		return;
@@ -545,6 +546,8 @@ ssh_packet_close(struct ssh *ssh)
 	sshbuf_free(state->output);
 	sshbuf_free(state->outgoing_packet);
 	sshbuf_free(state->incoming_packet);
+	for (mode = 0; mode < MODE_MAX; mode++)
+		kex_free_newkeys(state->newkeys[mode]);
 	if (state->compression_buffer) {
 		sshbuf_free(state->compression_buffer);
 		if (ssh->state->compression_out_started) {
diff --git a/ssh/ssh_api.c b/ssh/ssh_api.c
index cd2f825..d9b0787 100644
--- a/ssh/ssh_api.c
+++ b/ssh/ssh_api.c
@@ -96,9 +96,15 @@ ssh_init(struct ssh **sshp, int is_server, struct kex_params *kex_params)
 void
 ssh_free(struct ssh *ssh)
 {
+	u_int mode;
+
 	ssh_packet_close(ssh);
-	if (ssh->kex);
+	if (ssh->kex)
 		kex_free(ssh->kex);
+	for (mode = 0; mode < MODE_MAX; mode++) {
+		kex_free_newkeys(ssh->current_keys[mode]);
+		ssh->current_keys[mode] = NULL;
+	}
 	free(ssh);
 }
 
diff --git a/unittests/kex/test_kex.c b/unittests/kex/test_kex.c
index 11e5b72..8821f3d 100644
--- a/unittests/kex/test_kex.c
+++ b/unittests/kex/test_kex.c
@@ -101,7 +101,7 @@ do_kex_with_key(char *kex, int key_type, int bits)
 	ASSERT_INT_EQ(ssh_add_hostkey(client, public), 0);
 	TEST_DONE();
 
-	TEST_START(kex);
+	TEST_START("kex");
 	run_kex(client, server);
 	TEST_DONE();
 
@@ -148,6 +148,12 @@ do_kex_with_key(char *kex, int key_type, int bits)
 	ASSERT_INT_EQ(kex_send_kexinit(client), 0);
 	run_kex(client, server2);
 	TEST_DONE();
+
+	TEST_START("cleanup");
+	ssh_free(client);
+	ssh_free(server);
+	ssh_free(server2);
+	TEST_DONE();
 }
 
 static void