ikiwiki before 3.20161229 incorrectly called the CGI::FormBuilder->field method (similar to the CGI->param API that led to Bugzilla's CVE-2014-1572), which can be abused to lead to commit metadata forgery.

The confirm_create_account function in the account-creation feature in token.cgi in Bugzilla 2.x through 4.0.x before 4.0.15, 4.1.x and 4.2.x before 4.2.11, 4.3.x and 4.4.x before 4.4.6, and 4.5.x before 4.5.6 does not specify a scalar context for the realname parameter, which allows remote attackers to create accounts with unverified e-mail addresses by sending three realname values with realname=login_name as the second, as demonstrated by selecting an e-mail address with a domain name for which group privileges are automatically granted.