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             AUSCERT External Security Bulletin Redistribution

        CVE-2016-2776: Assertion Failure in buffer.c While Building
              Responses to a Specifically Constructed Request
                             28 September 2016


        AusCERT Security Bulletin Summary

Product:           BIND
Publisher:         Internet Systems Consortium
Operating System:  UNIX variants (UNIX, Linux, OSX)
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2016-2776  

Original Bulletin: 

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CVE-2016-2776: Assertion Failure in buffer.c While Building Responses to a 
Specifically Constructed Request

Author: Brian Conry 
Reference Number: AA-01419 
Created: 2016-09-27 08:30 
Last Updated: 2016-09-27 16:08



Document Version:


Posting date:


Program Impacted:


Versions affected:

9.0.x -> 9.8.x, 9.9.0->9.9.9-P2, 9.9.3-S1->9.9.9-S3, 9.10.0->9.10.4-P2, 






Testing by ISC has uncovered a critical error condition which can occur when a
nameserver is constructing a response. A defect in the rendering of messages 
into packets can cause named to exit with an assertion failure in buffer.c 
while constructing a response to a query that meets certain criteria.

This assertion can be triggered even if the apparent source address isn't 
allowed to make queries (i.e. doesn't match 'allow-query').


All servers are vulnerable if they can receive request packets from any 

CVSS Score: 7.8

CVSS Vector: (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: 


No practical workarounds exist.

Active exploits:

No known active exploits.

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

    BIND 9 version 9.9.9-P3

    BIND 9 version 9.10.4-P3

    BIND 9 version 9.11.0rc3

BIND 9 Supported Preview edition is a feature preview version of BIND provided
exclusively to eligible ISC Support customers.

    BIND 9 version 9.9.9-S5

Document Revision History:

1.0 Advance Notification 2016-09-14

1.1 Added information about the Stable Preview release to versions affected. 
Updated solution section to reflect replacing 9.11.0rc2 with 9.11.0rc3 and 
9.9.9-S4 with 9.9.9-S5.

2.0 Posting date changed and public disclosure.

Related Documents:

See our BIND9 Security Vulnerability Matrix at 
https://kb.isc.org/article/AA-00913 for a complete listing of Security 
Vulnerabilities and versions affected.

If you'd like more information on ISC Subscription Support and Advance 
Security Notifications, please visit http://www.isc.org/support/.

Do you still have questions? Questions regarding this advisory should go to 
security-officer@isc.org. To report a new issue, please encrypt your message 
using security-officer@isc.org's PGP key which can be found here: 
https://www.isc.org/downloads/software-support-policy/openpgp-key/. 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 http://www.isc.org/downloads/).

ISC Security Vulnerability Disclosure Policy: Details of our current security
advisory policy and practice can be found here: 

This Knowledge Base article https://kb.isc.org/article/AA-01419 is the 
complete and official security advisory document.

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