static void slaveMode(void) {
    int fd = context->fd;
    unsigned long long payload = sendSync(fd);
    char buf[1024];
    int original_output = config.output;

    fprintf(stderr,"SYNC with master, discarding %llu "
                   "bytes of bulk transfer...\n", payload);

    /* Discard the payload. */
    while(payload) {
        ssize_t nread;

        nread = read(fd,buf,(payload > sizeof(buf)) ? sizeof(buf) : payload);
        if (nread <= 0) {
            fprintf(stderr,"Error reading RDB payload while SYNCing\n");
            exit(1);
        }
        payload -= nread;
    }
    fprintf(stderr,"SYNC done. Logging commands from master.\n");

    /* Now we can use hiredis to read the incoming protocol. */
    config.output = OUTPUT_CSV;
    while (cliReadReply(0) == REDIS_OK);
    config.output = original_output;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.