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.
https://www.debian.org/security/2017/dsa-3760
https://security-tracker.debian.org/tracker/CVE-2016-9646