Fix #2366

src/manager.c

@@ -673,7 +673,7 @@ manager_recv_cb(EV_P_ ev_io *w, int revents)
         }
 
         size_t pos = strlen(buf);
-        strcpy(buf + pos - 1, "\n]"); // Remove trailing ","
+        strcpy(buf + max(pos - 1, 1), "\n]"); // Remove trailing ","
         pos = strlen(buf);
         if (sendto(manager->fd, buf, pos, 0, (struct sockaddr *)&claddr, len)
             != pos) {