OpenSSL

From https://github.com/openssl/openssl
"""
 Note: For legal reasons, contributions from the US can be accepted only
 if a TSU notification and a copy of the patch are sent to crypt@bis.doc.gov
 (formerly BXA) with a copy to the ENC Encryption Request Coordinator;
 please take some time to look at
    http://www.bis.doc.gov/Encryption/PubAvailEncSourceCodeNofify.html [sic]
 and
    http://w3.access.gpo.gov/bis/ear/pdf/740.pdf (EAR Section 740.13(e))
 for the details. If "your encryption source code is too large to serve as
 an email attachment", they are glad to receive it by fax instead; hope you
 have a cheap long-distance plan.
"""

So if you live in the "Land of the Free" you can only patch OpenSSL if you
tell the government what you're fixing. Despicable.