Several vulnerabilities were discovered in BIND, a DNS server implementation. CVE-2021-25214 Greg Kuechle discovered that a malformed incoming IXFR transfer could trigger an assertion failure in named, resulting in denial of service. CVE-2021-25215 Siva Kakarla discovered that named could crash when a DNAME record placed in the ANSWER section during DNAME chasing turned out to be the final answer to a client query. CVE-2021-25216 It was discovered that the SPNEGO implementation used by BIND is prone to a buffer overflow vulnerability. This update switches to use the SPNEGO implementation from the Kerberos libraries.