diff --git a/mongoose.c b/mongoose.c
index 710ded3d..325bbb35 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -15724,7 +15724,7 @@ struct tcp_recved_ctx {
 
 void tcp_recved_tcpip(void *arg) {
   struct tcp_recved_ctx *ctx = (struct tcp_recved_ctx *) arg;
-  tcp_recved(ctx->tpcb, ctx->len);
+  if (ctx->tpcb != NULL) tcp_recved(ctx->tpcb, ctx->len);
 }
 
 static int mg_lwip_if_tcp_recv(struct mg_connection *nc, void *buf,
diff --git a/src/common/platforms/lwip/mg_lwip_net_if.c b/src/common/platforms/lwip/mg_lwip_net_if.c
index d0777029..e78d93ce 100644
--- a/src/common/platforms/lwip/mg_lwip_net_if.c
+++ b/src/common/platforms/lwip/mg_lwip_net_if.c
@@ -581,7 +581,7 @@ struct tcp_recved_ctx {
 
 void tcp_recved_tcpip(void *arg) {
   struct tcp_recved_ctx *ctx = (struct tcp_recved_ctx *) arg;
-  tcp_recved(ctx->tpcb, ctx->len);
+  if (ctx->tpcb != NULL) tcp_recved(ctx->tpcb, ctx->len);
 }
 
 static int mg_lwip_if_tcp_recv(struct mg_connection *nc, void *buf,