On some RHEL or CentOS machines, when you do a "yum update" you might see the error - "Error: database disk image is malformed"

It is possible that due to some reason the yum repository got corrupted or cache was not cleaned in previous update cycle. In which case, you can get over the problem by running the below set of commands:-

 $sudo yum clean all
 $sudo yum clean metadata
 $sudo yum clean dbcache
 $sudo yum makecache

After you do the above, you could now try running "yum update" on the package you need

 $sudo yum update -y openssl