diff --git a/src/cm_mes/mes_tcp.c b/src/cm_mes/mes_tcp.c
index d29f145736fc1bd020413b139891c76ef23014fb..852c2938b602290d22f6848d4cc05f3cc6196117 100644
--- a/src/cm_mes/mes_tcp.c
+++ b/src/cm_mes/mes_tcp.c
@@ -265,6 +265,7 @@ static void mes_close_channel(mes_channel_t *channel)
     cm_rwlock_wlock(&channel->send_lock);
     if (channel->msgbuf != NULL) {
         free(channel->msgbuf);
+        channel->msgbuf = NULL;
     }
     cm_rwlock_unlock(&channel->send_lock);
 }