This issue can affect BIND 9 resolvers with `stale-answer-enable yes;` that also make use of the option `stale-answer-client-timeout`, configured with a value greater than zero.

If the resolver receives many queries that require recursion, there will be a corresponding increase in the number of clients that are waiting for recursion to complete. If there are sufficient clients already waiting when a new client query is received so that it is necessary to SERVFAIL the longest waiting client (see BIND 9 ARM `recursive-clients` limit and soft quota), then it is possible for a race to occur between providing a stale answer to this older client and sending an early timeout SERVFAIL, which may cause an assertion failure.
This issue affects BIND 9 versions 9.16.12 through 9.16.36, 9.18.0 through 9.18.10, 9.19.0 through 9.19.8, and 9.16.12-S1 through 9.16.36-S1.
Advisories
Source ID Title
Debian DSA Debian DSA DSA-5329-1 bind9 security update
EUVD EUVD EUVD-2022-43258 This issue can affect BIND 9 resolvers with `stale-answer-enable yes;` that also make use of the option `stale-answer-client-timeout`, configured with a value greater than zero. If the resolver receives many queries that require recursion, there will be a corresponding increase in the number of clients that are waiting for recursion to complete. If there are sufficient clients already waiting when a new client query is received so that it is necessary to SERVFAIL the longest waiting client (see BIND 9 ARM `recursive-clients` limit and soft quota), then it is possible for a race to occur between providing a stale answer to this older client and sending an early timeout SERVFAIL, which may cause an assertion failure. This issue affects BIND 9 versions 9.16.12 through 9.16.36, 9.18.0 through 9.18.10, 9.19.0 through 9.19.8, and 9.16.12-S1 through 9.16.36-S1.
Ubuntu USN Ubuntu USN USN-5827-1 Bind vulnerabilities
Fixes

Solution

Upgrade to the patched release most closely related to your current version of BIND 9: 9.16.37, 9.18.11, 9.19.9, or 9.16.37-S1.


Workaround

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.

History

Mon, 31 Mar 2025 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


cve-icon MITRE

Status: PUBLISHED

Assigner: isc

Published:

Updated: 2025-03-31T13:58:09.212Z

Reserved: 2022-11-10T09:07:37.642Z

Link: CVE-2022-3924

cve-icon Vulnrichment

Updated: 2024-08-03T01:20:58.777Z

cve-icon NVD

Status : Modified

Published: 2023-01-26T21:16:03.273

Modified: 2025-03-31T14:15:16.573

Link: CVE-2022-3924

cve-icon Redhat

Severity : Moderate

Publid Date: 2023-01-25T00:00:00Z

Links: CVE-2022-3924 - Bugzilla

cve-icon OpenCVE Enrichment

No data.