CVE-2019-6467: An error in the nxdomain redirect feature can cause BIND to exit with an INSIST assertion failure in query.c

Michael McNally mcnally at
Thu Apr 25 01:21:38 UTC 2019

CVE:                 CVE-2019-6467
Document version:    2.0
Posting date:        24 April 2019
Program impacted:    BIND
Versions affected:   BIND 9.12.0-> 9.12.4, 9.14.0. Also affects all releases
                     in the 9.13 development branch.
Severity:            Medium
Exploitable:         Remotely


   A programming error in the nxdomain-redirect feature can cause
   an assertion failure in query.c if the alternate namespace used
   by nxdomain-redirect is a descendant of a zone that is served

   The most likely scenario where this might occur is if the server,
   in addition to performing NXDOMAIN redirection for recursive
   clients, is also serving a local copy of the root zone or using
   mirroring to provide the root zone, although other configurations
   are also possible.


   An attacker who can deliberately trigger the condition on a
   server with a vulnerable configuration can cause BIND to exit,
   denying service to other clients.

CVSS Score:          5.9
CVSS Vector:         CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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


   Exploitation of this defect can be effectively prevented by
   disabling the nxdomain-redirect feature in the nameserver's

Active exploits:

   None known.


   Upgrade to the patched release most closely related to your current
version of BIND:

   -  BIND 9.12.4-P1
   -  BIND 9.14.1

Document revision history:

   1.0 Early Notification, 15 April 2019
   1.1 Removed BIND 9.11.6-P1 from Solution version list
   2.0 Public Disclosure, 24 April 2019

Related documents:

   See our BIND 9 Security Vulnerability Matrix for a complete
   listing of security vulnerabilities and versions affected.

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   versions are actively supported, please see

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