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             AUSCERT External Security Bulletin Redistribution

           CVE-2022-0667: Assertion failure on delayed DS lookup
                               17 March 2022


        AusCERT Security Bulletin Summary

Product:           Bind 9.18.0
Publisher:         ISC
Operating System:  UNIX variants (UNIX, Linux, OSX)
Resolution:        Patch/Upgrade
CVE Names:         CVE-2022-0667  

Original Bulletin: 

Comment: CVSS (Max):  7.0 CVE-2022-0667 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
         CVSS Source: ISC
         Calculator:  https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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CVE: CVE-2022-0667
Document version: 2.0
Posting date: 16 March 2022
Program impacted: BIND
Versions affected: BIND 9.18.0
Severity: High
Exploitable: Remotely


    In BIND 9.18.0 the recursive client code was refactored. This 
    introduced a "backstop lifetime timer".

    While BIND is processing a request for a DS record that needs to be
    forwarded, it waits until this processing is complete or until the 
    lifetime timer has timed out. When the `resume_dslookup()` function is
    called as a result of such a timeout, the function does not test whether
    the fetch has previously been shut down. This introduces the possibility
    of triggering an assertion failure, which could cause the BIND process
    to terminate.

    Only the BIND 9.18 branch is affected.


    When the vulnerability is triggered the BIND process will exit.

CVSS Score: 7.0


    For more information on the Common Vulnerability Scoring System and to
    obtain your specific environmental score, please visit:


    No workarounds known.

Active exploits:

    We are not aware of any active exploits.


    Users of BIND 9.18.0 should upgrade to BIND 9.18.1

Document revision history:

    1.0 Early Notification, 9 March 2022
    2.0 Public disclosure, 16 March 2022

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 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/pgpkey/. If you are unable to use encrypted email, you
may also report new issues at: https://www.isc.org/reportbug/.


ISC patches only currently supported versions. When possible we indicate
EOL versions affected. (For current information on which versions are
actively supported, please see https://www.isc.org/download/.)

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 at

This Knowledgebase article https://kb.isc.org/docs/cve-2022-0667 is
the complete and official security advisory document.

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Uncontrolled copies may lack important information, be out of date, or 
contain factual errors.

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