Using XML::XSH2, a wrapper around XML::LibXML: 
open file.xml ;
my $count = 0 ;
for //certDet {
    $count = $count + 1 ;
    echo :s Entry $count ':' ;
    echo :s 'DN="' xsh:subst(@subjectDN, ';', '&') '"' ;
    echo :s CN= xsh:match(@subjectDN, 'CN=(.*)') ;
    echo :s env= @env ;
    echo :s key= (key) ;
    
}

[download]
The output is a bit different from what you posted:
2c2
< DN="/C=US/ST=NC/L=Raleigh/O=DotNet/OU=ET&D/CN=test1.xxxx.com"
---
> DN="/C=US/ST=NC/L=Raleigh/O=DotNet/OU=ETD&D/CN=test1.xxxx.com"
9,10c9,10
< env=QA
< key=1234
---
> env=dev
> key=27166

[download]
لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

In reply to Re: extracting attribute values which might have multiple occurences from xml file by choroba
in thread extracting attribute values which might have multiple occurences from xml file by tinkuPerlMonk2

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.