Please refer CHANGES file for complete changes and here is quote from
release announce.
Introduction
BIND 9.9.3-P1 is the latest production release of BIND 9.9-ESV.
Security Fixes
Prevents exploitation of a runtime_check which can crash named
when satisfying a recursive query for particular malformed zones.
(CVE-2013-3919) [RT #33690]
Now supports NAPTR regular expression validation on all platforms,
and avoids memory exhaustion compiling pathological regular
expressions. (CVE-2013-2266) [RT #32688]
Prevents named from aborting with a require assertion failure
on servers with DNS64 enabled. These crashes might occur as a
result of specific queries that are received. (CVE-2012-5688)
[RT #30792 / #30996]
Prevents an assertion failure in named when RPZ and DNS64 are
used together. (CVE-2012-5689) [RT #32141]
New Features
Adds a new configuration option, "check-spf"; valid values are
"warn" (default) and "ignore". When set to "warn", checks SPF
and TXT records in spf format, warning if either resource record
type occurs without a corresponding record of the other resource
record type. [RT #33355]
Adds the command-line tool "dnssec-coverage" that checks to make
sure that there is no scheduled lapse in key coverage. Requires
python. [RT #28098]
Adds support for the EUI48 and EUI64 RR types. [RT #33082]
Adds support for the RFC 6742 ILNP record types (NID, LP, L32,
and L64). [RT #31836]
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