Application crashes on click of a QLabel that is set to open URL in browser

[rawfool]

I have a pop-up widget that shows on entering a specific cell of QTableWidget. And I'm closing the pop-up window on leave event.
The pop-up widget has got some QLabels, which are set as URLs. When I click on a hyperlink(QLabel), the link is opened in my browser. And when I click on another url Qlabel, the link is opened, but my application crashes immediately.

One observation is if the mouse is taken out of the pop-up window, before it takes time to open the link in the browser, the application doesn't crash.

//cpopupwindow.h
// this closes the window when the mouse is out of widget
protected:
    bool eventFilter(QObject * object, QEvent * event)
    {
        if(event->type() == QEvent::Leave)
        {
            if(isVisible())
            {
                while(!cveReferences.isEmpty())
                {
                    delete cveReferences.takeFirst();
                }
                this->close();
            }
        }
 
        return QWidget::eventFilter(object, event);
    }

//cpopupwindow.h
// this closes the window when the mouse is out of widget
protected:
    bool eventFilter(QObject * object, QEvent * event)
    {
        if(event->type() == QEvent::Leave)
        {
            if(isVisible())
            {
                while(!cveReferences.isEmpty())
                {
                    delete cveReferences.takeFirst();
                }
                this->close();
            }
        }

        return QWidget::eventFilter(object, event);
    }

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// in cpopupwindow.cpp
    this->installEventFilter(this); //in ctor
 
// this is a public function which displays the content and is called in tablewidget class on cellEnter()
void CPopupWindow::someFunction() 
{
// This is how I add the text to QLabels
    if("CVE" == repoType)
    {
        cceReference_table->setVisible(false);
        for(int i = 0; i < lst.count(); i++)
        {
            cveReferences.append(new QLabel());
            cveReferences.at(i)->setText("<a href=\"" + references.value(lst.at(i)) + "\">" +
                                         lst.at(i) + "</a>");
            cveReferences.at(i)->setTextFormat(Qt::RichText);
            cveReferences.at(i)->setTextInteractionFlags(Qt::TextBrowserInteraction);
            cveReferences.at(i)->setOpenExternalLinks(true);
            vLyt->addWidget(cveReferences.at(i));
        }
    }
}

// in cpopupwindow.cpp
    this->installEventFilter(this); //in ctor

// this is a public function which displays the content and is called in tablewidget class on cellEnter()
void CPopupWindow::someFunction() 
{
// This is how I add the text to QLabels
    if("CVE" == repoType)
    {
        cceReference_table->setVisible(false);
        for(int i = 0; i < lst.count(); i++)
        {
            cveReferences.append(new QLabel());
            cveReferences.at(i)->setText("<a href=\"" + references.value(lst.at(i)) + "\">" +
                                         lst.at(i) + "</a>");
            cveReferences.at(i)->setTextFormat(Qt::RichText);
            cveReferences.at(i)->setTextInteractionFlags(Qt::TextBrowserInteraction);
            cveReferences.at(i)->setOpenExternalLinks(true);
            vLyt->addWidget(cveReferences.at(i));
        }
    }
}

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Everything is fine until second click of the URL. On second click, if the mouse is not taken out of pop-up widget, then the whole application crashes.
Kindly help me with this. Thank you.