diff --git a/mongoose.c b/mongoose.c
index f4cbb927..961fcebc 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -1923,7 +1923,7 @@ static void mqtt_login(struct mg_connection *c, const char *url,
 
 void mg_mqtt_pub(struct mg_connection *c, struct mg_str *topic,
                  struct mg_str *data, int qos, bool retain) {
-  uint8_t flags = (uint8_t)((qos & 3) << 1) | (retain ? 1 : 0);
+  uint8_t flags = (uint8_t)(((qos & 3) << 1) | (retain ? 1 : 0));
   uint32_t total_len = 2 + (uint32_t) topic->len + (uint32_t) data->len;
   LOG(LL_DEBUG, ("%lu [%.*s] -> [%.*s]", c->id, (int) topic->len,
                  (char *) topic->ptr, (int) data->len, (char *) data->ptr));
diff --git a/src/mqtt.c b/src/mqtt.c
index 38299529..1d7f394d 100644
--- a/src/mqtt.c
+++ b/src/mqtt.c
@@ -83,7 +83,7 @@ static void mqtt_login(struct mg_connection *c, const char *url,
 
 void mg_mqtt_pub(struct mg_connection *c, struct mg_str *topic,
                  struct mg_str *data, int qos, bool retain) {
-  uint8_t flags = (uint8_t)((qos & 3) << 1) | (retain ? 1 : 0);
+  uint8_t flags = (uint8_t)(((qos & 3) << 1) | (retain ? 1 : 0));
   uint32_t total_len = 2 + (uint32_t) topic->len + (uint32_t) data->len;
   LOG(LL_DEBUG, ("%lu [%.*s] -> [%.*s]", c->id, (int) topic->len,
                  (char *) topic->ptr, (int) data->len, (char *) data->ptr));