Skip to content
CVE Tracker
  • Newest CVEsPage
  • Recently added to KEVPage
  • Rising exploitation (EPSS)Page
  • Weekly digestPage
  • StatisticsPage
  • WatchlistPage
  • API documentationPage
  • MCP serverPage
  • Data sourcesPage
  • ChangelogPage
  • AboutPage
  • How it's builtPage
Back

CVE-2022-3924

named configured to answer from stale cache may terminate unexpectedly at recursive-clients soft quota

High7.5EPSS 16.0%
Published
Updated
Reserved
Assigned by
isc

Description

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.

Timeline

  1. ID reserved

    By isc

  2. · 3 months later

    Published

  3. · 2 years later

    Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2022-3924, by who scored it
Scored byCVSSScoreVector
iscCNA (assigner)3.1High7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVDNVD · Modified3.1High7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (exploitation in 30 days)
16.0% · top 3.1% of all CVEs (7 Nov 2026)
CISA SSVC
Exploitation: none · Automatable: yes · Technical impact: partial
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

Affected products

  • ISC · BIND 9

    • affected 9.16.12 – ≤ 9.16.36
    • affected 9.18.0 – ≤ 9.18.10
    • affected 9.19.0 – ≤ 9.19.8
    • affected 9.16.12-S1 – ≤ 9.16.36-S1

What to do

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.

Exploitation: We are not aware of any active exploits.

References (1)

Sources

The same CVE in the primary databases and aggregators, to check against.

Badge for a README or a ticket

CVE-2022-3924 badge
[![CVE-2022-3924](https://trackcve.app/badge/CVE-2022-3924.svg)](https://trackcve.app/cve/CVE-2022-3924)

Record last updated .