Check for RHEL 6.5-specific updates (though most will move you toward 6.6, 6.7, etc. if you run a full yum update ). To stay on 6.5 but backport security fixes, you need ELS and careful repository pinning.
The “RHEL 6.5 updated ISO download” is not recommended unless obtained directly from Red Hat with a valid subscription. Unofficial versions are a security risk and legally questionable. For modern use, pick a supported RHEL 8/9 or a free rebuild like AlmaLinux. Check for RHEL 6
Red Hat does release refreshed ISOs for point releases. Instead: The “RHEL 6
: Because RHEL 6.5 is over a decade old and well past its maintenance phase, it contains known security vulnerabilities. It should only be used in isolated environments or for legacy software compatibility. Red Hat Customer Portal verifying a SHA-256 checksum Red Hat does release refreshed ISOs for point releases