Joomla! before 1.5.12 does not perform a JEXEC check in unspecified files, which allows remote attackers to obtain the installation path via unspecified vectors.
http://www.securityfocus.com/bid/35544
http://www.openwall.com/lists/oss-security/2011/12/25/8
http://www.openwall.com/lists/oss-security/2011/12/25/3
http://secunia.com/advisories/35668
http://developer.joomla.org/security/news/300-20090606-core-missing-jexec-check.html