The MySQL 5.5.39 and 5.6.20 releases fix an unspecified certificate decoding issue in yaSSL:
"yaSSL code had an off-by-one error in certificate decoding that could cause buffer overflow."
Created mariadb tracking bugs for this issue:
Affects: fedora-all [bug 1126274]
Created community-mysql tracking bugs for this issue:
Affects: fedora-all [bug 1126273]
MySQL upstream commit:
This fixes an off-by-one issue in the handling of validity start and end dates in X.509 certificates. Value written past the end of buffer is '\0'. Additionally, overwrite should only clobber other members of the CertDecoder class, hence it does not seem this should lead to direct code execution. However, as it might lead to overwrite of verify_ field, it may lead to bypass of certificate verification.
MySQL and MariaDB packages shipped in Red Hat products and Fedora use system OpenSSL library to implement TLS/SSL. Embedded yaSSL is not used, hence those packages are not affected by this issue.
Not vulnerable. This issue did not affect the versions of MySQL and MariaDB as shipped with Red Hat Enterprise Linux 5, 6, and 7, and Red Hat Software Collections 1.