XineramaConstrainCursor(DeviceIntPtr pDev)
{
    SpritePtr pSprite = pDev->spriteInfo->sprite;
    ScreenPtr pScreen;
    BoxRec newBox;

    pScreen = pSprite->screen;
    newBox = pSprite->physLimits;

    /* Translate the constraining box to the screen
       the sprite is actually on */
    newBox.x1 += screenInfo.screens[0]->x - pScreen->x;
    newBox.x2 += screenInfo.screens[0]->x - pScreen->x;
    newBox.y1 += screenInfo.screens[0]->y - pScreen->y;
    newBox.y2 += screenInfo.screens[0]->y - pScreen->y;

    (*pScreen->ConstrainCursor) (pDev, pScreen, &newBox);
}

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.