If I understood your earlier reply correctly, the regex does match (with the alternation), but it doesn't match the way you want. That's a big difference, and what I tried to explain to you.
That's the behavior I want with regards to the rest of the records.

After looking at the updated data I think that you need two regexes for that: 

use strict;
use warnings;

my $str = do { local $/; <DATA> };

if ($str =~ m/Remediation Report\n\n(.+?)\n/g){
    print $1, $/;
    while ($str =~ m/\n\n(.*)\n/g){
        print $1, $/;

    }
}

__DATA__
thread-index: AcjoCau17Ri90HMJR8qoukn2A1g7ng==
MIME-Version: 1.0
# rest of data goes here

[download]

The output is: 

Adobe Flash Player Multiple Vulnerabilities - April 2008 - IE    
Adobe Flash Player Multiple Vulnerabilities - April 2008 - Mozilla/Ope
+ra
Adobe Reader/Acrobat 8.1.2 and 7.1.0 Update - Acrobat 7.x

[download]

The trick is to use the /g-modifier on the first regex although it matches only once. That way pos $str will not be reset, and the next regex match starts where the previous left off.

Also note that ^ will anchor to the start of the string (not to the start of a line) unless the /m modifier is present.

In reply to Re^5: Regex problems using '|' by moritz
in thread Regex problems using '|' by romandas

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