Untrusted search path vulnerability in libX11.so in xfree86, when used in setuid or setgid programs, allows local users to gain root privileges via a modified LD_PRELOAD environment variable that points to a malicious module.
http://www.securityfocus.com/bid/5735
http://www.redhat.com/support/errata/RHSA-2003-067.html
http://www.redhat.com/support/errata/RHSA-2003-066.html
http://www.iss.net/security_center/static/10137.php
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000529
http://archives.neohapsis.com/archives/linux/suse/2002-q3/1116.html