static void cirrus_bitblt_cputovideo_next(CirrusVGAState * s)
{
    int copy_count;
    uint8_t *end_ptr;

    if (s->cirrus_srccounter > 0) {
        if (s->cirrus_blt_mode & CIRRUS_BLTMODE_PATTERNCOPY) {
            cirrus_bitblt_common_patterncopy(s, s->cirrus_bltbuf);
        the_end:
            s->cirrus_srccounter = 0;
            cirrus_bitblt_reset(s);
        } else {
            /* at least one scan line */
            do {
                (*s->cirrus_rop)(s, s->vga.vram_ptr +
                                 (s->cirrus_blt_dstaddr & s->cirrus_addr_mask),
                                  s->cirrus_bltbuf, 0, 0, s->cirrus_blt_width, 1);
                cirrus_invalidate_region(s, s->cirrus_blt_dstaddr, 0,
                                         s->cirrus_blt_width, 1);
                s->cirrus_blt_dstaddr += s->cirrus_blt_dstpitch;
                s->cirrus_srccounter -= s->cirrus_blt_srcpitch;
                if (s->cirrus_srccounter <= 0)
                    goto the_end;
                /* more bytes than needed can be transferred because of
                   word alignment, so we keep them for the next line */
                /* XXX: keep alignment to speed up transfer */
                end_ptr = s->cirrus_bltbuf + s->cirrus_blt_srcpitch;
                copy_count = s->cirrus_srcptr_end - end_ptr;
                memmove(s->cirrus_bltbuf, end_ptr, copy_count);
                s->cirrus_srcptr = s->cirrus_bltbuf + copy_count;
                s->cirrus_srcptr_end = s->cirrus_bltbuf + s->cirrus_blt_srcpitch;
            } while (s->cirrus_srcptr >= s->cirrus_srcptr_end);
        }
    }
}

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.