ActivateKeyboardGrab(DeviceIntPtr keybd, GrabPtr grab, TimeStamp time,
                     Bool passive)
{
    GrabInfoPtr grabinfo = &keybd->deviceGrab;
    GrabPtr oldgrab = grabinfo->grab;
    WindowPtr oldWin;

    /* slave devices need to float for the duration of the grab. */
    if (grab->grabtype == XI2 && keybd->enabled &&
        !(passive & ImplicitGrabMask) && !IsMaster(keybd))
        DetachFromMaster(keybd);

    if (!keybd->enabled)
        oldWin = NULL;
    else if (grabinfo->grab)
        oldWin = grabinfo->grab->window;
    else if (keybd->focus)
        oldWin = keybd->focus->win;
    else
        oldWin = keybd->spriteInfo->sprite->win;
    if (oldWin == FollowKeyboardWin)
        oldWin = keybd->focus->win;
    if (keybd->valuator)
        keybd->valuator->motionHintWindow = NullWindow;
    if (oldWin)
        DoFocusEvents(keybd, oldWin, grab->window, NotifyGrab);
    if (syncEvents.playingEvents)
        grabinfo->grabTime = syncEvents.time;
    else
        grabinfo->grabTime = time;
    grabinfo->grab = AllocGrab(grab);
    grabinfo->fromPassiveGrab = passive;
    grabinfo->implicitGrab = passive & ImplicitGrabMask;
    CheckGrabForSyncs(keybd, (Bool) grab->keyboardMode,
                      (Bool) grab->pointerMode);
    if (oldgrab)
        FreeGrab(oldgrab);
}

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.