Opera 7.50 and earlier allows remote web sites to provide a "Shortcut Icon" (favicon) that is wider than expected, which could allow the web sites to spoof a trusted domain and facilitate phishing attacks using a wide icon and extra spaces.
https://exchange.xforce.ibmcloud.com/vulnerabilities/16307
http://marc.info/?l=bugtraq&m=108627581717738&w=2
http://lists.grok.org.uk/pipermail/full-disclosure/2004-June/022263.html