title: An error in the nxdomain redirect feature can cause BIND to exit with an INSIST assertion failure in query.c
description: 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 locally. 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. Versions affected: BIND 9.12.0-> 9.12.4, 9.14.0. Also affects all releases in the 9.13 development branch.
problem types: 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.
affected:
{
product: BIND 9
vendor: ISC
versions:
status: affected, version: BIND 9.12.0-> 9.12.4, 9.14.0. Also affects all releases in the 9.13 development branch.
}
metrics:
cvssV3_0: [
attackComplexity: HIGH
attackVector: NETWORK
availabilityImpact: HIGH
baseScore: 5.9
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
version: 3.0
]
solutions: Upgrade to the patched release most closely related to your current version of BIND:
+   BIND 9.12.4-P1
+   BIND 9.14.1
workarounds: Exploitation of this defect can be effectively prevented by disabling the nxdomain-redirect feature in the nameserver's configuration.