The ACL plugin in Dovecot before 1.1.4 treats negative access rights as if they are positive access rights, which allows attackers to bypass intended access restrictions.
bugs.gentoo.org/show_bug.cgi?id=240409
lists.opensuse.org/opensuse-security-announce/2009-02/msg00002.html
secunia.com/advisories/32164
secunia.com/advisories/32471
secunia.com/advisories/33149
secunia.com/advisories/33624
secunia.com/advisories/36904
security.gentoo.org/glsa/glsa-200812-16.xml
www.dovecot.org/list/dovecot-news/2008-October/000085.html
www.mandriva.com/security/advisories?name=MDVSA-2008:232
www.redhat.com/support/errata/RHSA-2009-0205.html
www.securityfocus.com/bid/31587
www.ubuntu.com/usn/USN-838-1
www.vupen.com/english/advisories/2008/2745
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10376
www.redhat.com/archives/fedora-package-announce/2008-October/msg00816.html
www.redhat.com/archives/fedora-package-announce/2008-October/msg00844.html