CGI versions before 5.00 for Perl return request-derived values untainted under taint mode.
The upload filename, uploadInfo values, some path_info and script_name values, Accept results, and the name lists from url_param and cookie are returned without the taint flag, as is a cookie named expires from 4.67 on.
These values come from regex captures or hash keys, which Perl does not taint, so they pass -T checks unvalidated.
Improper Use of Validation Framework The product does not use, or incorrectly uses, an input validation framework that is provided by the source language, framework, or an independent library.