CVE-2022-2795: Processing large delegations may severely degrade resolver performance
  • 21 Sep 2022
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CVE-2022-2795: Processing large delegations may severely degrade resolver performance

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Article summary

CVE: CVE-2022-2795

Document version: 2.0

Posting date: 21 September 2022

Program impacted: BIND

Versions affected:


  • 9.0.0 -> 9.16.32
  • 9.18.0 -> 9.18.6
  • 9.19.0 -> 9.19.4

BIND Supported Preview Edition

  • 9.9.3-S1 -> 9.11.37-S1
  • 9.16.8-S1 -> 9.16.32-S1

Severity: Medium

Exploitable: Remotely


A flaw in resolver code can cause named to spend excessive amounts of time on processing large delegations.


By flooding the target resolver with queries exploiting this flaw an attacker can significantly impair the resolver's performance, effectively denying legitimate clients access to the DNS resolution service.

CVSS Score: 5.3


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.


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

  • 9.16.33
  • 9.18.7
  • 9.19.5

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

  • 9.16.33-S1


ISC would like to thank Yehuda Afek from Tel-Aviv University and Anat Bremler-Barr & Shani Stajnrod from Reichman University for bringing this vulnerability to our attention.

Document revision history:

1.0 Early Notification, 14 September 2022
1.1 Minor punctuation corrections, 19 September 2022
2.0 Public disclosure, 21 September 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 be mailed 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 at

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

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