diff --git a/src/server.c b/src/server.c
index 69e13c60..b96c4fe7 100644
--- a/src/server.c
+++ b/src/server.c
@@ -2402,6 +2402,12 @@ int processCommand(client *c) {
      * is returning an error. */
     if (server.maxmemory) {
         int retval = freeMemoryIfNeeded();
+        /* freeMemoryIfNeeded may flush slave output buffers. This may result
+         * into a slave, that may be the active client, to be freed. */
+        if (server.current_client == NULL) return C_ERR;
+
+        /* It was impossible to free enough memory, and the command the client
+         * is trying to execute is denied during OOM conditions? Error. */
         if ((c->cmd->flags & CMD_DENYOOM) && retval == C_ERR) {
             flagTransaction(c);
             addReply(c, shared.oomerr);