"Bad stub:" is not mentioned anywhere in OPs message

If the eval() dies due to taint modus (and not just returns undef because of normal failure), the or croak part will never executed. So not relevant.

$ perl -Te 'eval shift or die "NO"' foo
Insecure dependency in eval while running with -T switch at -e line 1.
$ no NO printed, see?
[download]

• Code execution error" doesn't appear in SOAP/Lite.pm
• "returned error" doesn't appear in SOAP/Lite.pm

So it was wrapped in some other code that caught the error, and augmented with additional information. It looks to me that the line in question is still the source of the error, even if indirectly reported.

Gah, I kept focusing on $_ being a hash key and thus not tainted

Cheap fix

sub generate_stub {
...

    $self->{'_stub'} = $1 if $self->{'_stub'} =~ /^(.*)/;
    return $self->stub;
}
[download]