diff --git a/src/channel.c b/src/channel.c
index c8c4d4e..70d5045 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -1697,6 +1697,25 @@ LIBSSH2_API int libssh2_channel_free(LIBSSH2_CHANNEL *channel)
         session->channels.tail = channel->prev;
     }
 
+    /*
+     * Make sure all memory used in the state variables are free
+     */
+    if (channel->setenv_packet) {
+        LIBSSH2_FREE(session, channel->setenv_packet);
+    }
+    if (channel->reqPTY_packet) {
+        LIBSSH2_FREE(session, channel->reqPTY_packet);
+    }
+    if (channel->reqX11_packet) {
+        LIBSSH2_FREE(session, channel->reqX11_packet);
+    }
+    if (channel->process_packet) {
+        LIBSSH2_FREE(session, channel->process_packet);
+    }
+    if (channel->write_packet) {
+        LIBSSH2_FREE(session, channel->write_packet);
+    }
+    
     LIBSSH2_FREE(session, channel);
 
     return 0;
diff --git a/src/publickey.c b/src/publickey.c
index cb593f6..31db3d6 100644
--- a/src/publickey.c
+++ b/src/publickey.c
@@ -864,6 +864,22 @@ LIBSSH2_API void libssh2_publickey_shutdown(LIBSSH2_PUBLICKEY *pkey)
 {
     LIBSSH2_SESSION *session = pkey->channel->session;
 
+    /*
+     * Make sure all memory used in the state variables are free
+     */
+    if (pkey->receive_packet) {
+        LIBSSH2_FREE(session, pkey->receive_packet);
+    }
+    if (pkey->add_packet) {
+        LIBSSH2_FREE(session, pkey->add_packet);
+    }
+    if (pkey->remove_packet) {
+        LIBSSH2_FREE(session, pkey->remove_packet);
+    }
+    if (pkey->listFetch_data) {
+        LIBSSH2_FREE(session, pkey->listFetch_data);
+    }
+    
     libssh2_channel_free(pkey->channel);
     LIBSSH2_FREE(session, pkey);
 }
diff --git a/src/session.c b/src/session.c
index d76e055..ba180d7 100644
--- a/src/session.c
+++ b/src/session.c
@@ -576,10 +576,12 @@ LIBSSH2_API int libssh2_session_startup(LIBSSH2_SESSION *session, int socket)
         if ((session->startup_service_length != (sizeof("ssh-userauth") - 1)) ||
             strncmp("ssh-userauth", (char *)session->startup_data + 5, session->startup_service_length)) {
             LIBSSH2_FREE(session, session->startup_data);
+            session->startup_data = NULL;
             libssh2_error(session, LIBSSH2_ERROR_PROTO, "Invalid response received from server", 0);
             return LIBSSH2_ERROR_PROTO;
         }
         LIBSSH2_FREE(session, session->startup_data);
+        session->startup_data = NULL;
         
         session->startup_state = libssh2_NB_state_idle;
         
@@ -702,6 +704,52 @@ LIBSSH2_API void libssh2_session_free(LIBSSH2_SESSION *session)
         LIBSSH2_FREE(session, session->remote.lang_prefs);
     }
 
+    /*
+     * Make sure all memory used in the state variables are free
+     */
+    if (session->startup_data) {
+        LIBSSH2_FREE(session, session->startup_data);
+    }
+    if (session->disconnect_data) {
+        LIBSSH2_FREE(session, session->disconnect_data);
+    }
+    if (session->userauth_data) {
+        LIBSSH2_FREE(session, session->userauth_data);
+    }
+    if (session->userauth_newpw) {
+        LIBSSH2_FREE(session, session->userauth_newpw);
+    }
+    if (session->userauth_packet) {
+        LIBSSH2_FREE(session, session->userauth_packet);
+    }
+    if (session->userauth_method) {
+        LIBSSH2_FREE(session, session->userauth_method);
+    }
+    if (session->userauth_auth_instruction) {
+        LIBSSH2_FREE(session, session->userauth_auth_instruction);
+    }
+    if (session->open_packet) {
+        LIBSSH2_FREE(session, session->open_packet);
+    }
+    if (session->open_data) {
+        LIBSSH2_FREE(session, session->open_data);
+    }
+    if (session->direct_message) {
+        LIBSSH2_FREE(session, session->direct_message);
+    }
+    if (session->fwdLstn_packet) {
+        LIBSSH2_FREE(session, session->fwdLstn_packet);
+    }
+    if (session->pkeyInit_data) {
+        LIBSSH2_FREE(session, session->pkeyInit_data);
+    }
+    if (session->scpRecv_command) {
+        LIBSSH2_FREE(session, session->scpRecv_command);
+    }
+    if (session->scpSend_command) {
+        LIBSSH2_FREE(session, session->scpSend_command);
+    }
+    
     /* Cleanup any remaining packets */
     while (session->packets.head) {
         LIBSSH2_PACKET *tmp = session->packets.head;
@@ -768,6 +816,7 @@ LIBSSH2_API int libssh2_session_disconnect_ex(LIBSSH2_SESSION *session, int reas
     }
 
     LIBSSH2_FREE(session, session->disconnect_data);
+    session->disconnect_data = NULL;
     session->disconnect_state = libssh2_NB_state_idle;
 
     return 0;
diff --git a/src/sftp.c b/src/sftp.c
index ef24037..bcfc649 100644
--- a/src/sftp.c
+++ b/src/sftp.c
@@ -656,6 +656,46 @@ LIBSSH2_API LIBSSH2_SFTP *libssh2_sftp_init(LIBSSH2_SESSION *session)
  */
 LIBSSH2_API int libssh2_sftp_shutdown(LIBSSH2_SFTP *sftp)
 {
+    /*
+     * Make sure all memory used in the state variables are free
+     */
+    if (sftp->partial_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->partial_packet);
+    }
+    if (sftp->open_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->open_packet);
+    }
+    if (sftp->read_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->read_packet);
+    }
+    if (sftp->readdir_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->readdir_packet);
+    }
+    if (sftp->write_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->write_packet);
+    }
+    if (sftp->fstat_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->fstat_packet);
+    }
+    if (sftp->unlink_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->unlink_packet);
+    }
+    if (sftp->rename_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->rename_packet);
+    }
+    if (sftp->mkdir_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->mkdir_packet);
+    }
+    if (sftp->rmdir_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->rmdir_packet);
+    }
+    if (sftp->stat_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->stat_packet);
+    }
+    if (sftp->symlink_packet) {
+        LIBSSH2_FREE(sftp->channel->session, sftp->symlink_packet);
+    }
+    
     return libssh2_channel_free(sftp->channel);
 }
 /* }}} */
diff --git a/src/userauth.c b/src/userauth.c
index d13e880..83e6d00 100644
--- a/src/userauth.c
+++ b/src/userauth.c
@@ -274,6 +274,7 @@ libssh2_userauth_password_ex(LIBSSH2_SESSION *session, const char *username, uns
                             libssh2_error(session, LIBSSH2_ERROR_ALLOC,
                                           "Unable to allocate memory for userauth-password-change request", 0);
                             LIBSSH2_FREE(session, session->userauth_newpw);
+                            session->userauth_newpw = NULL;
                             return -1;
                         }