CVE-2019-6468: BIND Supported Preview Edition can exit with an assertion failure if nxdomain-redirect is used
  • 16 Oct 2019
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CVE-2019-6468: BIND Supported Preview Edition can exit with an assertion failure if nxdomain-redirect is used

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Article summary

CVE: CVE-2019-6468

Document version: 2.0

Posting date: 24 April 2019

Program impacted: BIND

Versions affected: BIND Supported Preview Edition version 9.10.5-S1 -> 9.11.5-S5. ONLY BIND Supported Preview Edition releases are affected.

Severity: Medium

Exploitable: Remotely


In BIND Supported Preview Edition, an error in the nxdomain-redirect feature can occur in versions which support EDNS Client Subnet (ECS) features. In those versions which have ECS support, enabling nxdomain-redirect is likely to lead to BIND exiting due to assertion failure.


If nxdomain-redirect is enabled (via configuration) in a vulnerable BIND release, a malicious party can cause BIND to exit by deliberately triggering the bug.

CVSS Score: 5.9


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 configuration.

Active exploits:

None known.


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

BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers.

  • BIND 9.11.5-S6
  • BIND 9.11.6-S1

Document revision history:

1.0 Early Notification, 15 April 2019
1.1 Added reference to BIND 9.11.6-S1 in Solution section
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.

Do you still have questions? Questions regarding this advisory should go to To report a new issue, please encrypt your message using's PGP key which can be found here: If you are unable to use encrypted email, you may also report new issues at:


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

ISC Security Vulnerability Disclosure Policy:

Details of our current security advisory policy and practice can be found in the ISC Software Defect and Security Vulnerability Disclosure Policy.

This Knowledgebase article is the complete and official security advisory document.

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