diff --git a/src/ssb.c b/src/ssb.c
index da47e6bc..cdd5f63a 100644
--- a/src/ssb.c
+++ b/src/ssb.c
@@ -579,6 +579,11 @@ static void _tf_ssb_connection_box_stream_send(tf_ssb_connection_t* connection,
 	{
 		size_t send_size = size - offset > k_send_max ? k_send_max : size - offset;
 		uint8_t* message_enc = tf_malloc(send_size + 34);
+		if (!message_enc)
+		{
+			tf_ssb_connection_close(connection, "out of memory");
+			return;
+		}
 
 		uint8_t nonce1[crypto_secretbox_NONCEBYTES];
 		memcpy(nonce1, connection->send_nonce, sizeof(nonce1));