This affects sites with the `git` VCS and the `recentchanges` plugin,
which are both used in most ikiwiki installations.
-This bug was reported on 2016-12-17. The fixed version 3.20161219
-was released on 2016-12-19.
+This bug was reported on 2016-12-17. A partially fixed version
+3.20161219 was released on 2016-12-19, but the solution used in that
+version was not effective with git versions older than 2.8.0.
+
+([[!cve CVE-2016-10026]] represents the original vulnerability.
+[[!cve CVE-2016-9645]]/OVE-20161226-0002 represents the vulnerability
+in 3.20161219 caused by the incomplete fix.)
+
+## Commit metadata forgery via CGI::FormBuilder context-dependent APIs
+
+When CGI::FormBuilder->field("foo") is called in list context (and
+in particular in the arguments to a subroutine that takes named
+arguments), it can return zero or more values for foo from the CGI
+request, rather than the expected single value. This breaks the usual
+Perl parsing convention for named arguments, similar to CVE-2014-1572
+in Bugzilla (which was caused by a similar API design issue in CGI.pm).
+
+In ikiwiki, this appears to have been exploitable in two places, both
+of them relatively minor:
+
+* in the comments plugin, an attacker who was able to post a comment
+ could give it a user-specified author and author-URL even if the wiki
+ configuration did not allow for that, by crafting multiple values
+ for other fields
+* in the editpage plugin, an attacker who was able to edit a page
+ could potentially forge commit authorship (attribute their edit to
+ someone else) by crafting multiple values for the rcsinfo field
+
+([[!cve CVE-2016-9646]]/OVE-20161226-0001)