An unusually-formed answer containing a DS resource record could trigger an assertion failure. While the combination of properties which triggers the assertion should not occur in normal traffic, it is potentially possible for the assertion to be triggered deliberately by an attacker sending a specially-constructed answer having the required properties.

This vulnerability occurs during the processing of an answer packet received in response to a query. As a result, recursive servers are at the greatest risk; authoritative servers are at risk only to the extent that they perform a limited set of queries.

This description is borrowed from the upstream advisory.

BIND was improperly sequencing cleanup operations on upstream recursion fetch contexts, leading in some cases to a use-after-free error that can trigger an assertion failure and crash in named. Affects BIND 9.0.0 to 9.8.x, 9.9.0 to 9.9.11, 9.10.0 to 9.10.6, 9.11.0 to 9.11.2, 9.9.3-S1 to 9.9.11-S1, 9.10.5-S1 to 9.10.6-S1, 9.12.0a1 to 9.12.0rc1.

The BIND installer on Windows uses an unquoted service path which can enable a local user to achieve privilege escalation if the host file system permissions allow this. Affects BIND 9.2.6-P2->9.2.9, 9.3.2-P1->9.3.6, 9.4.0->9.8.8, 9.9.0->9.9.10, 9.10.0->9.10.5, 9.11.0->9.11.1, 9.9.3-S1->9.9.10-S1, 9.10.5-S1.

An attacker who is able to send and receive messages to an authoritative DNS server and who has knowledge of a valid TSIG key name for the zone and service being targeted may be able to manipulate BIND into accepting an unauthorized dynamic update. A server that relies solely on TSIG or SIG(0) keys with no other address-based ACL protection could be vulnerable to malicious zone content manipulation using this technique.

Workarounds:

The effects of this vulnerability can be mitigated by using Access Control Lists (ACLs) that require both address range validation and use of TSIG authentication in parallel. For information on how to configure this type of compound authentication control, please see:

https://kb.isc.org/article/AA-00723/0/Using-Access-Control-Lists-ACLs-with-both-addresses-and-keys.html.

Administrators who have made use of named.conf option "update-policy local;" should refer to the Administrator Reference Manual (ARM) for details of the automatic update policy that will be established and to assess whether or not this conveys any additional risk to their server. (Note that this option is not enabled by default).

Upstream patch:

https://source.isc.org/cgi-bin/gitweb.cgi?p=bind9.git;a=commitdiff;h=581c1526ab

ISC reports a cache poisoning flaw reported by Michael Sinatra of UC Berkeley that may cause bind to cache replies that were not properly DNSSEC validated when recursive query was done based on uncommon client query.

A nameserver with DNSSEC validation enabled may incorrectly add records to its cache from the additional section of responses received during resolution of a recursive client query. This behavior only occurs when processing client queries with checking disabled (CD) at the same time as requesting DNSSEC records (DO).

This issue was reported to affect all 9.x versions and should be fixed in 9.4.3-P4, 9.5.2-P1 and 9.6.1-P2.

query.c in ISC BIND 9.0.x through 9.6.x, 9.4-ESV through 9.4-ESV-R5, 9.6-ESV through 9.6-ESV-R5, 9.7.0 through 9.7.4, 9.8.0 through 9.8.1, and 9.9.0a1 through 9.9.0b1 allows remote attackers to cause a denial of service (assertion failure and named exit) via unknown vectors related to recursive DNS queries, error logging, and the caching of an invalid record by the resolver.

Common Vulnerabilities and Exposures assigned an identifier CVE-2011-1910 to the following vulnerability:

A BIND 9 DNS server set up to be a caching resolver is vulnerable to a user querying a domain with very large resource record sets (RRSets) when trying to negatively cache a response. This can cause the BIND 9 DNS server (named process) to crash.

http://www.isc.org/software/bind/advisories/cve-2011-1910

ISC BIND 9.x before 9.7.6-P4, 9.8.x before 9.8.3-P4, 9.9.x before 9.9.1-P4, and 9.4-ESV and 9.6-ESV before 9.6-ESV-R7-P4 allows remote attackers to cause a denial of service (named daemon hang) via unspecified combinations of resource records.

ISC BIND 9.x before 9.7.6-P3, 9.8.x before 9.8.3-P3, 9.9.x before 9.9.1-P3, and 9.4-ESV and 9.6-ESV before 9.6-ESV-R7-P3 allows remote attackers to cause a denial of service (assertion failure and named daemon exit) via a query for a long resource record.

ISC BIND 9.4.x, 9.5.x, 9.6.x, and 9.7.x before 9.7.6-P2; 9.8.x before 9.8.3-P2; 9.9.x before 9.9.1-P2; and 9.6-ESV before 9.6-ESV-R7-P2, when DNSSEC validation is enabled, does not properly initialize the failing-query cache, which allows remote attackers to cause a denial of service (assertion failure and daemon exit) by sending many queries.

ISC BIND 9.0.x through 9.8.x, 9.9.0 through 9.9.6, and 9.10.0 through 9.10.1 does not limit delegation chaining, which allows remote attackers to cause a denial of service (memory consumption and named crash) via a large or infinite number of referrals.

buffer.c in named in ISC BIND 9.10.x before 9.10.3-P3, when debug logging is enabled, allows remote attackers to cause a denial of service (REQUIRE assertion failure and daemon exit, or daemon crash) or possibly have unspecified other impact via (1) OPT data or (2) an ECS option.

apl42.c in ISC BIND 9.x before 9.9.8-P3, 9.9.x, and 9.10.x before 9.10.3-P3 allows remote authenticated users to cause a denial of service (INSIST assertion failure and daemon exit) via a malformed Address Prefix List (APL) record.

Race condition in resolver.c in named in ISC BIND 9.9.8 before 9.9.8-P2 and 9.10.3 before 9.10.3-P2 allows remote attackers to cause a denial of service (INSIST assertion failure and daemon exit) via unspecified vectors.

db.c in named in ISC BIND 9.x before 9.9.8-P2 and 9.10.x before 9.10.3-P2 allows remote attackers to cause a denial of service (REQUIRE assertion failure and daemon exit) via a malformed class attribute.

A packet with a malformed options section can be used to deliberately trigger an assertion failure affecting versions of BIND which do not contain change #3548.

A server vulnerable to this defect can be forced to exit with an assertion failure if it receives a malformed packet. Authoritative and recursive servers are both vulnerable.

https://source.isc.org/cgi-bin/gitweb.cgi?p=bind9.git;a=blob;f=CHANGES has more information on change #3548. The commit corresponding to this change is https://source.isc.org/cgi-bin/gitweb.cgi?p=bind9.git;a=commitdiff;h=4adf97c32fcca7d00e5756607fd045f2aab9c3d4.