CURL-CVE-2023-27535

FTP too eager connection reuse

libcurl would reuse a previously created FTP connection even when one or more options had been changed that could have made the effective user a different one, thus leading to doing the second transfer with the wrong credentials. libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, several FTP settings were left out from the configuration match checks, making them match too easily. The settings in questions are `CURLOPT_FTP_ACCOUNT`, `CURLOPT_FTP_ALTERNATIVE_TO_USER`, `CURLOPT_FTP_SSL_CCC` and `CURLOPT_USE_SSL` level.