CVE-2022-3094: 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 o...

Description

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. This issue affects BIND 9 versions 9.16.0 through 9.16.36, 9.18.0 through 9.18.10, 9.19.0 through 9.19.8, and 9.16.8-S1 through 9.16.36-S1.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

13.11%

95.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Isc	Bind	>= 9.16.0, < 9.16.37	—
Isc	Bind	>= 9.18.0, < 9.18.11	—
Isc	Bind	>= 9.19.0, < 9.19.9	—
Isc	Bind	9.16.8	S1
Isc	Bind	9.16.11	S1
Isc	Bind	9.16.13	S1
Isc	Bind	9.16.14	S1
Isc	Bind	9.16.21	S1
Isc	Bind	9.16.32	S1
Isc	Bind	9.16.36	S1

References

https://kb.isc.org/docs/cve-2022-3094Vendor Advisory
https://kb.isc.org/docs/cve-2022-3094Vendor Advisory

Timeline

Published: Jan 26, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-3094?

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. This issue affects BIND 9 versions 9.16.0 through 9.16.36, 9.18.0 through 9.18.10, 9.19.0 through 9.19.8, and 9.16.8-S1 through 9.16.36-S1.

How severe is CVE-2022-3094?

CVE-2022-3094 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 13.11% probability of exploitation in the next 30 days.

How do I fix CVE-2022-3094?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.