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In reply to Comment by Reader F30

Andrew Ayer on 2020-05-30 at 23:24:

Are you aware that there is at least one other current Root CA which used to be cross-signed by "AddTrust External CA Root" - "COMODO RSA Certification Authority"? ( , old cross-signed cert is )

Yes. will catch this case.

Additionally there is another variant of the "USERTrust RSA Certification Authority" cert ( ) issued by the "AAA Certificate Services" Root CA ( ). That one should still be valid until 2028.

Including this certificate in your chain is a good option if you need to support really old clients that don't have "USERTrust RSA Certification Authority" in their trust stores. However, there's a caveat: since "AAA Certificate Services" isn't enabled for EV by Apple, Mozilla, or Chrome, your expensive EV certificate might not get EV treatment. That said, EV certificates are silly ;-)

However, cURL on macOS 10.14 (built against LibreSSL 2.6.5) also fails to connect to servers sending a security chain containing the latter. This is interesting, since "AddTrust External CA Root" never occurs in that chain. One example for it is

The chain that I see ends in "AddTrust External CA Root" not "AAA Certificate Services".


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