The following issue has been fixed in MySQL:
"Unspecified vulnerability in Oracle MySQL Server 5.5.38 and earlier,
and 5.6.19 and earlier, allows remote attackers to affect availability
via vectors related to SERVER:SSL:yaSSL."
MySQL packages in Red Hat Enterprise Linux and Fedora are built against system OpenSSL and do not use bundled yaSSL. Hence they can not be affected by any yaSSL issues.
This issue did not affect the versions of mysql as shipped with Red Hat Enterprise Linux 5, 6, and 7, as they use system OpenSSL library rather than yaSSL.