UBUNTU-CVE-2026-120639: Medium severity ubuntu/libcgi-pm-perl vulnerability

CGI versions before 5.00 for Perl allow HTTP header injection via entity decoding after the newline check in header and unchecked values in multipartstart and dopush. With autoEscape off, header decodes HTML entities in extra header values after its newline check, so an encoded CR or LF reaches the response. multipartstart does not check header values for newlines, and dopush does not check the type it prints in each part. An application that passes request data into these header values can be made to add headers or split the response.