I think it’s not thread safe as Crypt::SSLeay doesn’t talk about thread safety. Though Net::SSLeay does talk about resetting callbacks to undef to prevent thread safety problems and crashes on exit. So far I have ignored this due to following reason.

1. I believed LWP (and Mechanize as well) uses Crypt::SSLeay for HTTPS.
2. Other than login page (which is hit at start of the script) there are no https links, therefore I was not sure about the use of SSLeay.dll

I can try to reset callbacks if that seems to be an issue, however not sure what to do if my assumption about use of Crypt::SSLeay (and not Net::SSLeay is used for HTTPS) is correct.