The strip_tags function in PHP 4.x up to 4.3.7, and 5.x up to 5.0.0RC3, does not filter null (\0) characters within tag names when restricting input to allowed tags, which allows dangerous tags to be processed by web browsers such as Internet Explorer and Safari, which ignore null characters and facilitate the exploitation of cross-site scripting (XSS) vulnerabilities.
distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000847
lists.grok.org.uk/pipermail/full-disclosure/2004-July/023909.html
marc.info/?l=bugtraq&m=108981780109154&w=2
marc.info/?l=bugtraq&m=108982983426031&w=2
marc.info/?l=bugtraq&m=109051444105182&w=2
marc.info/?l=bugtraq&m=109181600614477&w=2
www.debian.org/security/2004/dsa-531
www.debian.org/security/2005/dsa-669
www.gentoo.org/security/en/glsa/glsa-200407-13.xml
www.mandrakesecure.net/en/advisories/advisory.php?name=MDKSA-2004:068
www.novell.com/linux/security/advisories/2004_21_php4.html
www.redhat.com/support/errata/RHSA-2004-392.html
www.redhat.com/support/errata/RHSA-2004-395.html
www.redhat.com/support/errata/RHSA-2004-405.html
www.redhat.com/support/errata/RHSA-2005-816.html
www.securityfocus.com/bid/10724
exchange.xforce.ibmcloud.com/vulnerabilities/16692
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10619