squid_ldap_auth in Squid 2.5 and earlier allows remote authenticated users to bypass username-based Access Control Lists (ACLs) via a username with a space at the beginning or end, which is ignored by the LDAP server.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10251
http://www.squid-cache.org/bugs/show_bug.cgi?id=1187
http://www.squid-cache.org/Versions/v2/2.5/bugs/squid-2.5.STABLE7-ldap_spaces.patch
http://www.squid-cache.org/Versions/v2/2.5/bugs/#squid-2.5.STABLE7-ldap_spaces
http://www.securityfocus.com/bid/12431
http://www.redhat.com/support/errata/RHSA-2005-061.html
http://www.redhat.com/support/errata/RHSA-2005-060.html
http://www.novell.com/linux/security/advisories/2005_06_squid.html
http://www.mandriva.com/security/advisories?name=MDKSA-2005:034
http://www.kb.cert.org/vuls/id/924198
http://www.debian.org/security/2005/dsa-667
http://marc.info/?l=bugtraq&m=110780531820947&w=2
http://fedoranews.org/updates/FEDORA--.shtml
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000923