The myuser_delete function in libathemecore/account.c in Atheme 5.x before 5.2.7, 6.x before 6.0.10, and 7.x before 7.0.0-beta2 does not properly clean up CertFP entries when a user is deleted, which allows remote attackers to access a different user account or cause a denial of service (daemon crash) via a login as a deleted user.
http://www.securityfocus.com/bid/52675
http://www.openwall.com/lists/oss-security/2012/03/23/2
http://www.openwall.com/lists/oss-security/2012/03/22/3
http://security.gentoo.org/glsa/glsa-201209-09.xml
http://secunia.com/advisories/50704
http://secunia.com/advisories/48481
http://jira.atheme.org/browse/SRV-166
http://git.atheme.org/atheme/commit/?id=3d9551761db2
http://archives.neohapsis.com/archives/fulldisclosure/2012-03/0248.html