Certificates/PEM Files

Sometimes when trying to clone a git repo off the internet, I run into this error: SSL certificate problem: certificate has expired. On old versions of Mac OSX, your system's SSL cert may not update, so you should update it manually[1].

OpenSSL on macOS does not use the system keychain (which makes sense as it's a cross platform library) but rather has its own .pem file containing its root certificates. Even though my systems have a newer version of OpenSSL installed using homebrew and/or MacPorts, the system-wide OpenSSL pem file located at /etc/ssl/cert.pem was out of date and did not include the ISRG Root X1 certificate.

The solution:

  • Rename /etc/ssl/cert.pem to something else. (I suggest /etc/ssl/cert.pem.org)
  • Download the latest cacert.pem from https://curl.se/docs/caextract.html
  • Rename it to cert.pem
  • Copy it to /etc/ssl/cert.pem

Now curl and any other app using OpenSSL can access websites signed using current Let's Encrypt certificates.

Alternatively, the MacPorts package curl-ca-bundle installs a .pem file containing ISRG Root X1 to /opt/local/etc/openssl/cert.pem which can be used as well.

Other possible solutions:

  • Manually add the ISRG Root X1 certificate to /etc/ssl/cert.pem
  • Configure OpenSSL to use a different .pem file for its root certificates, such as /opt/local/etc/openssl/cert.pem


  1. https://stackoverflow.com/questions/69521959/ssl-certificate-problem-certificate-has-expire-in-macos

Last modified: 202212070107