CVE-2022-3094: An UPDATE message flood may cause named to exhaust all available memory
  • 25 Jan 2023
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CVE-2022-3094: An UPDATE message flood may cause named to exhaust all available memory

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Article Summary

CVE: CVE-2022-3094

Document version: 2.1

Posting date: 25 January 2023

Program impacted: BIND 9

Versions affected:


  • 9.16.0 -> 9.16.36
  • 9.18.0 -> 9.18.10
  • 9.19.0 -> 9.19.8

(Versions prior to 9.11.37 were not assessed.)

BIND Supported Preview Edition

  • 9.16.8-S1 -> 9.16.36-S1

(Versions prior to 9.11.37-S1 were not assessed.)

Severity: High

Exploitable: Remotely


Sending a flood of dynamic DNS updates may cause named to allocate large amounts of memory. This, in turn, may cause named to exit due to a lack of free memory. We are not aware of any cases where this has been exploited.

Memory is allocated prior to the checking of access permissions (ACLs) and is retained during the processing of a dynamic update from a client whose access credentials are accepted. Memory allocated to clients that are not permitted to send updates is released immediately upon rejection. The scope of this vulnerability is limited therefore to trusted clients who are permitted to make dynamic zone changes.

If a dynamic update is REFUSED, memory will be released again very quickly. Therefore it is only likely to be possible to degrade or stop named by sending a flood of unaccepted dynamic updates comparable in magnitude to a query flood intended to achieve the same detrimental outcome.

BIND 9.11 and earlier branches are also affected, but through exhaustion of internal resources rather than memory constraints. This may reduce performance but should not be a significant problem for most servers. Therefore we don't intend to address this for BIND versions prior to BIND 9.16.


By flooding the target server with UPDATE requests, the attacker can exhaust all available memory on that server.

CVSS Score: 7.5


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:

  • 9.16.37
  • 9.18.11
  • 9.19.9

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

  • 9.16.37-S1


ISC would like to thank Rob Schulhof from Infoblox for bringing this vulnerability to our attention.

Document revision history:

  • 1.0 Early Notification, 18 January 2023
  • 2.0 Public disclosure, 25 January 2023
  • 2.1 Correction to BIND Supported Preview Edition affected versions, 25 January 2023

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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