diff --git a/src/networking.c b/src/networking.c
index 82c763c95fbaa62f4c07140943e3b46213a1e3db..00f5bab027e49f65c8be3da1b19fd640a2953a5b 100644
--- a/src/networking.c
+++ b/src/networking.c
@@ -1944,6 +1944,7 @@ int checkClientOutputBufferLimits(client *c) {
  * called from contexts where the client can't be freed safely, i.e. from the
  * lower level functions pushing data inside the client output buffers. */
 void asyncCloseClientOnOutputBufferLimitReached(client *c) {
+    if (c->fd == -1) return; /* It is unsafe to free fake clients. */
     serverAssert(c->reply_bytes < SIZE_MAX-(1024*64));
     if (c->reply_bytes == 0 || c->flags & CLIENT_CLOSE_ASAP) return;
     if (checkClientOutputBufferLimits(c)) {