modules/chanserv/flags.c in Atheme before 7.2.7 allows remote attackers to modify the Anope FLAGS behavior by registering and dropping the (1) LIST, (2) CLEAR, or (3) MODIFY keyword nicks.
https://github.com/atheme/atheme/issues/397
https://github.com/atheme/atheme/commit/c597156adc60a45b5f827793cd420945f47bc03b
http://www.openwall.com/lists/oss-security/2016/05/03/1
http://www.openwall.com/lists/oss-security/2016/05/02/2
http://lists.opensuse.org/opensuse-updates/2016-05/msg00061.html