xps_true_callback_decode_glyph(gs_font *pfont, gs_glyph glyph, int ch, ushort *unicode_return, unsigned int length)
{
    xps_font_t *font = pfont->client_data;
    char *ur = (char *)unicode_return;
    int u;

    if (length == 0)
        return 2;
    u = xps_decode_font_char(font, glyph);
    /* Unfortunate assumptions in the pdfwrite code mea that we have to return the
     * value as a big-endian short, no matter what platform we are on
     */
    ur[1] = u & 0xff;
    ur[0] = u >> 8;
    return 2;
}

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.