CVE-2014-0591: A Crafted Query Against an NSEC3-signed Zone Can Crash BIND
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CVE-2014-0591: A Crafted Query Against an NSEC3-signed Zone Can Crash BIND

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Article Summary

An unintentional defect in the handling of NSEC3-signed zones can cause BIND to be crashed by a specific set of queries.

CVE: CVE-2014-0591

Document version: 2.0

Posting date: 13 Jan 2014

Program impacted: BIND

Versions affected: 9.6.0.x -> 9.6-ESV-R10-P1, 9.7 (all versions), 9.8.0 -> 9.8.6-P1, 9.9.0 -> 9.9.4-P1. Development releases 9.6-ESV-R11b1, 9.8.7b1, and 9.9.5b1 are also affected.

Severity: High

Exploitable: Remotely


Because of a defect in handling queries for NSEC3-signed zones, BIND can crash with an "INSIST" failure in name.c when processing queries possessing certain properties. By exploiting this defect, an attacker deliberately constructing a query with the right properties could achieve denial of service against an authoritative nameserver serving NSEC3-signed zones.

Please note: Versions of BIND 9.7 are also affected, but this branch is beyond its "end of life" (EOL) and no longer receives testing or security fixes from ISC. For current information on which versions are actively supported, please see


Authoritative nameservers serving at least one NSEC3-signed zone are vulnerable to this defect. Recursive-only servers are not at risk.  Authoritative servers which do not serve NSEC3-signed zones are not at risk.

CVSS Score: 5.4

CVSS Vector: (AV:N/AC:H/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:

Workarounds: None.

Active exploits:

There are no known active exploits but limited discussion of this issue has taken place on a public mailing list.

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

  • BIND 9 version 9.6-ESV-R10-P2
  • BIND 9 version 9.8.6-P2
  • BIND 9 version 9.9.4-P2

Acknowledgements:  ISC would like to thank Jared Mauch for reporting this issue.

Document Revision History:

1.0 Phase One, Advance Notification, 06 January 2014
1.1 Phase One+, Advance Notification, 08 January 2014
1.2 Phase Two & Three, Advance Notification, 10 January 2014
1.3 Changed CVSS Equation to Vector and edited Exploits, 11 January 2014
2.0 Phase Four, Public Release, 13 January 2014

Related Documents:

If you'd like more information on ISC Subscription Support and Advance Security Notifications, please visit

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 security-officer@isc.orgTo 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:

Note: 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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