An authentication bypass vulnerability exists in libcurl <8.0.0 in the FTP connection reuse feature that can result in wrong credentials being used during subsequent transfers. Previously created connections are kept in a connection pool for reuse if they match the current setup. However certain FTP settings such as CURLOPT_FTP_ACCOUNT CURLOPT_FTP_ALTERNATIVE_TO_USER CURLOPT_FTP_SSL_CCC and CURLOPT_USE_SSL were not included in the configuration match checks causing them to match too easily. This could lead to libcurl using the wrong credentials when performing a transfer potentially allowing unauthorized access to sensitive information.