slapd in OpenLDAP 2.0 through 2.0.19 allows local users, and anonymous users before 2.0.8, to conduct a "replace" action on access controls without any values, which causes OpenLDAP to delete non-mandatory attributes that would otherwise be protected by ACLs.
https://exchange.xforce.ibmcloud.com/vulnerabilities/7978
http://www1.itrc.hp.com/service/cki/docDisplay.do?docId=HPSBTL0201-020
http://www.securityfocus.com/bid/3945
http://www.redhat.com/support/errata/RHSA-2002-014.html
http://www.openldap.org/lists/openldap-announce/200201/msg00002.html
http://frontal2.mandriva.com/security/advisories?name=MDKSA-2002:013
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000459