In Wordpress, when trying to install a Theme, view the RSS or performing other operations that use CURL, the following error message appeared:
SSL certificate problem, verify that the CA cert is OK.
Details: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
This is because Wordpress is using its own certificate bundle, overriding the global system certificate bundle. The problem is that the certificate bundle that Wordpress has is old and needs to be updated. To do this, please download the latest one from http://curl.haxx.se/ca/cacert.pem and save it as ca-bundle.crt
Note: the best way to download it is by right clicking on the link above, and select "Download Linked File" (Safari), or "Save Link As..." (Firefox, Chrome). Alternatively you can use the browser menu File -> Save As, but you must upload the file as ASCII / Text mode, not Binary.
Upload this file to: wp-includes/certificates/ca-bundle.crt