CVE-2012-3817: Heavy DNSSEC Validation Load Can Cause a "Bad Cache" Assertion Failure in BIND 9
  • 10 Dec 2018
  • 3 Minutes to read
  • Contributors
  • Dark
  • PDF

CVE-2012-3817: Heavy DNSSEC Validation Load Can Cause a "Bad Cache" Assertion Failure in BIND 9

  • Dark
  • PDF

Article Summary

Title: Heavy DNSSEC Validation Load Can Cause a "Bad Cache" Assertion Failure in BIND 9

Summary: High numbers of queries with DNSSEC validation enabled can cause an assertion failure in named, caused by using a "bad cache" data structure before it has been initialized.

CVE: CVE-2012-3817

Document version: 2.3

Posting date: 24 July, 2012

Program impacted: BIND 9

Versions affected: 9.6-ESV through 9.6-ESV-R7-P1; 9.7.1 through 9.7.6-P1; 9.8.0 through 9.8.3-P1; 9.9.0 through 9.9.1-P1.

Severity: Critical

Exploitable: Remotely


BIND 9 stores a cache of query names that are known to be failing due to misconfigured name servers or a broken chain of trust. Under high query loads when DNSSEC validation is active, it is possible for a condition to arise in which data from this cache of failing queries could be used before it was fully initialized, triggering an assertion failure.

This bug cannot be encountered unless your server is doing DNSSEC validation.

Please note: Versions of BIND 9.4 and 9.5 are also affected, but these branches are beyond their "end of life" (EOL) and no longer receive testing or security fixes from ISC. For current information on which versions are actively supported, please see

CVSS Score: 7.8

CVSS Equation: (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:

Workarounds: None

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

  • BIND 9 version 9.9.1-P2
  • BIND 9 version 9.8.3-P2
  • BIND 9 version 9.7.6-P2
  • BIND 9 version 9.6-ESV-R7-P2

Exploit Status: None known at this time

Acknowledgment: ISC would like to thank Einar Lonn of

Document Revision History:

1.0 - 11 July, 2012 Phase 1 notice sent
1.1 - 17 July, 2012 Phase 1 re-issued due to change in patch for CVE-2012-3868 that affects 9.9.x only
1.2 - 23 July, 2012 Phase 2 & 3 sent
2.0 - 24 July, 2012 Phase 3 (Public) notified
2.1 - 30 July, 2012 Added Chinese translation
2.2 - 6 August, 2012 Added link to article with additional information/FAQs
2.3 - 12 December 2014 Versions Affected now includes 9.6-ESV (previously 9.6-ESV-R1 through 9.6-ESV-R7-P1)


- Japanese Translation:

- Spanish Translation:

- German Translation:

- Chinese Translation:

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.

Legal Disclaimer:
Internet Systems Consortium (ISC) is providing this notice on an "AS IS" basis. No warranty or guarantee of any kind is expressed in this notice and none should be implied. ISC expressly excludes and disclaims any warranties regarding this notice or materials referred to in this notice, including, without limitation, any implied warranty of merchantability, fitness for a particular purpose, absence of hidden defects, or of non-infringement. Your use or reliance on this notice or materials referred to in this notice is at your own risk. ISC may change this notice at any time.  A stand-alone copy or paraphrase of the text of this document that omits the document URL is an uncontrolled copy. Uncontrolled copies may lack important information, be out of date, or contain factual errors.