CVE-2022-3924

A flaw was found in Bind. When resolver receives many queries requiring recursion, there will be a corresponding increase in the number of clients waiting for recursion to complete. This may, under certain conditions, lead to an assertion failure and a denial of service.

The flaw exists in the implementation of the stale-answer-client-timeout option, which was first effectively introduced in BIND 9.16.12

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Disabling stale-answer-client-timeout entirely or setting the timeout value to zero prevents the problem.

It is not possible to disable the limit on recursive-clients, though it could be set to a very high value in order to reduce the likelihood of encountering this scenario. However, this is not recommended as the limit on recursive clients is important for preventing exhaustion of server resources.