This update for bind fixes the following issues: Security issues fixed: - CVE-2018-5740: Fixed a denial of service vulnerability in the quot;deny-answer-aliasesquot; feature . - CVE-2018-5743: Limiting simultaneous TCP clients is ineffective. - CVE-2018-5745: An assertion failure can occur if a trust anchor rolls over to an unsupported key algorithm when using managed-keys. - CVE-2019-6465: Fixed an issue where controls for zone transfers may not be properly applied to Dynamically Loadable Zones .