CVE-2015-5722: Parsing malformed keys may cause BIND to exit due to a failed assertion in buffer.c

Michael McNally mcnally at
Wed Sep 2 19:55:25 UTC 2015

CVE:                       CVE-2015-5722
Document Version:          2.0
Posting date:              2 September 2015
Program Impacted:          BIND
Versions affected:         BIND 9.0.0 -> 9.8.8,  BIND 9.9.0 -> 9.9.7-P2, and
                           BIND 9.10.0 -> 9.10.2-P3
Severity:                  Critical
Exploitable:               Remotely


   Parsing a malformed DNSSEC key can cause a validating resolver
   to exit due to a failed assertion in buffer.c.  It is possible
   for a remote attacker to deliberately trigger this condition,
   for example by using a query which requires a response from a
   zone containing a deliberately malformed key.


   Recursive servers are at greatest risk but an authoritative
   server could be affected if an attacker controls a zone the
   server must query against to perform its zone service.

   Servers which are affected may terminate with an assertion
   failure, causing denial of service to all clients.

CVSS Score:                7.8
CVSS Vector:               (AV:N/AC:L/Au:N/C:N/I:N/A:C)

   For more information on the Common Vulnerability Scoring System
   and to obtain your specific environmental score please visit:


   Servers which are not performing validation are not at risk from
   this defect (but are at increased risk from other types of DNS
   attack.)  ISC does not recommend disabling validation to deal with
   this issue; upgrading to a fixed version is the preferred solution.

Active exploits:

   None known


   Upgrade to the patched release most closely related to your
   current version of BIND. These can all be downloaded from

   +  BIND 9 version 9.9.7-P3
   +  BIND 9 version 9.10.2-P4

   BIND development releases scheduled to be published at the same
   time as the public disclosure of this vulnerability will also
   contain the fix for this security issue.

   +  BIND 9 version 9.9.8rc1
   +  BIND 9 version 9.10.3rc1


   ISC would like to thank Hanno Boeck from the Fuzzing Project for
   discovering and reporting this defect.  We would also like to
   express our appreciation to the developers of the American Fuzzy
   Lop tool, which has been instrumental in revealing recently-disclosed
   vulnerabilities in BIND.

Document Revision History:

   1.0 Advance Notification 19 August 2015
   1.1 "Versions affected" information clarified  24 August, 2015
   2.0 Public Disclosure  2 September, 2015

Related Documents:

   See our BIND9 Security Vulnerability Matrix at for a complete listing of
   Security Vulnerabilities and versions affected.

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   Advance Security Notifications, please visit

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   ISC patches only currently supported versions. When possible we
   indicate EOL versions affected.  (For current information on which
   versions are actively supported, please see

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