perldoc -f use

$$ perl -Mblib=CGI.pm-2.56 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.56/blib
<FORM METHOD="POST"  ENCTYPE="application/x-www-form-urlencoded">
2.56 at -e line 1.

$$ perl -Mblib=CGI.pm-2.81 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.81/blib
<form method="post" action="/-e" enctype="application/x-www-form-urlen
+coded">
2.81 at -e line 1.

$$ perl -Mblib=CGI.pm-2.84 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.84/blib
<form method="post" action="/-e" enctype="application/x-www-form-urlen
+coded">
2.84 at -e line 1.

$$ perl -Mblib=CGI.pm-2.85 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.85/blib
<form method="post" action="/-e" enctype="application/x-www-form-urlen
+coded">
2.85 at -e line 1.

$$ perl -Mblib=CGI.pm-2.86 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.86/blib
<form method="post" action="/-e" enctype="application/x-www-form-urlen
+coded">
2.86 at -e line 1.

$$ perl -Mblib=CGI.pm-2.90 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.90/blib
<form method="post" action="/-e" enctype="application/x-www-form-urlen
+coded">
2.90 at -e line 1.

$$ perl -Mblib=CGI.pm-2.91 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.91/blib
<form method="post" action="/-e" enctype="application/x-www-form-urlen
+coded">
2.91 at -e line 1.

$$ perl -Mblib=CGI.pm-2.92 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.92/blib
<form method="post" action="/-e" enctype="application/x-www-form-urlen
+coded">
2.92 at -e line 1.

$$ perl -Mblib=CGI.pm-2.93 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.93/blib
<form method="post" action="/-e" enctype="application/x-www-form-urlen
+coded">
2.93 at -e line 1.

$$ perl -Mblib=CGI.pm-2.94 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.94/blib
<form method="post" action="/-e" enctype="application/x-www-form-urlen
+coded">
2.94 at -e line 1.

$$ perl -Mblib=CGI.pm-2.95 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
CGI.pm-2.95 is not a directory
BEGIN failed--compilation aborted.

$$ perl -Mblib=CGI.pm-2.97 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.97/blib
<form method="post" action="/-e" enctype="application/x-www-form-urlen
+coded">
2.97 at -e line 1.

$$ perl -Mblib=CGI.pm-2.98 -MCGI -e"warn CGI->start_form();die CGI->ve
+rsion"
Using CGI.pm-2.98/blib
<form method="post" action="/-e" enctype="application/x-www-form-urlen
+coded">
2.98 at -e line 1.

$$ perl -MCGI -e"warn CGI->start_form();die CGI->version"
<form method="post" action="%2F-e" enctype="application/x-www-form-url
+encoded">
2.99 at -e line 1.
[download]

CGI.pm's html generation functions are famous for this kind of thing. On a side node, I vaguely recall that apache, or some versions of it, do seem to interpret %2F as a / before a ?, so /a%2Fb/ is interpreted as /a/b/.

I'm not sure what the RFCs say, so I suggest you find out what it's supposed to be, and then figure out if that's the wrong behaviour on behalf of CGI.pm.

MJD says "you can't just make shit up and expect the computer to know what you mean, retardo!"

I run a Win32 PPM repository for perl 5.6.x and 5.8.x -- I take requests (README).

** The third rule of perl club is a statement of fact: pod is sexy.