[jmestwa-coder]

CertificateSigningRequest.extensions used whichever extension request attribute came first and ignored any others:

• OpenSSL and LibreSSL always take the PKCS#9 attribute over the Microsoft one, and Go merges every PKCS#9 attribute
• DER SET OF ordering follows the encoded bytes, so the requester chooses which attribute comes first
• the added vector reads as CA:FALSE here, while openssl x509 -req -copy_extensions copy (3.5.4) issues it as critical CA:TRUE

Now raises ValueError when more than one is present, with a regression vector and test.

[alex]

This does not require a changelog entry.

[jmestwa-coder]

Dropped it.