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BindApplication · Isc

CVE-2022-3736

HIGH · 7.5 CVSS v3.1 Published 2023-01-26
Fix available
A fix is available. Upgrade to 9.16.37 / 9.18.11 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
BIND 9 resolver can crash when stale cache and stale answers are enabled, option `stale-answer-client-timeout` is set to a positive integer, and the resolver receives an RRSIG query. 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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The BIND 9 DNS resolver crashes when stale cache and stale answers are enabled, the stale-answer-client-timeout option is set to a positive integer, and the resolver receives an RRSIG (Resource Record Signature) query. This combination triggers a NULL pointer dereference or similar memory error causing the resolver process to terminate, resulting in denial of service.

MitigationUpgrade to BIND 9 versions 9.16.37, 9.18.11, 9.19.9, or 9.16.37-S1 and later. Alternatively, set stale-answer-client-timeout to 0 or disable stale answers entirely as a workaround.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
BindApplication
Affected:>= 9.16.12, < 9.16.37>= 9.18.0, < 9.18.11>= 9.19.0, < 9.19.9= 9.16.11= 9.16.13= 9.16.14= 9.16.21= 9.16.32= 9.16.36

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify BIND 9 version
    Run 'named -v' or 'named -V' to get the installed BIND version, or check the package manager output (e.g., 'rpm -q bind', 'dpkg -l bind9').
    Affected if The installed version falls within >= 9.16.12 < 9.16.37, >= 9.18.0 < 9.18.11, >= 9.19.0 < 9.19.9, or equals one of: 9.16.11, 9.16.13, 9.16.14, 9.16.21, 9.16.32, 9.16.36.
  2. Locate BIND configuration files
    Check for named.conf (or named.conf.include files) in /etc/, /etc/bind/, or the directory specified with '-c' option when starting named. Look for 'include' directives to find all loaded configuration files.
    Affected if Configuration files exist and are readable for the next checks.
  3. Check stale-answer-client-timeout setting
    Search configuration files for 'stale-answer-client-timeout' using 'grep -r "stale-answer-client-timeout" /etc/' or manually inspect the config. If not set, BIND defaults to 0 (disabled).
    Affected if The option is set to a positive integer (e.g., 'stale-answer-client-timeout 500;' or any value greater than 0).
  4. Verify stale answers are enabled
    Search for 'stale-answers-enable yes;' or 'stale-answers-allow-expired yes;' in configuration files. Also check for 'stale-cache-enable yes;' which may enable stale answers implicitly.
    Affected if Stale answers or stale cache is explicitly enabled with 'yes' or 'on'.

The environment is affected only if: (1) the BIND version is vulnerable, (2) stale-answer-client-timeout is set to a positive integer, AND (3) stale answers or stale cache is enabled. All three conditions must be true for the crash to trigger.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 9.16.37 / 9.18.11 / 9.19.9 or later
Fixed in 9.16.379.18.119.19.9
Interim mitigation

Upgrade to BIND 9 versions 9.16.37, 9.18.11, 9.19.9, or 9.16.37-S1 and later. Alternatively, set stale-answer-client-timeout to 0 or disable stale answers entirely as a workaround.

Recommended fix High confidence

9.16.37 (for 9.16.x branch), 9.18.11 (for 9.18.x branch), or 9.19.9 (for 9.19.x branch)

  1. 1. Check your current BIND version by running 'named -v' or 'bind -v'
  2. 2. Identify if the 'stale-answer-client-timeout' option is configured in your named.conf (look for 'stale-answer-client-timeout <positive integer>' in the options block)
  3. 3. If running an affected version AND using stale-answer-client-timeout, plan for immediate upgrade
  4. 4. For BIND 9.16.x: upgrade to version 9.16.37
  5. 5. For BIND 9.18.x: upgrade to version 9.18.11
  6. 6. For BIND 9.19.x: upgrade to version 9.19.9
  7. 7. After upgrade, verify the new version is running with 'named -v'
  8. 8. Test DNS resolution functionality, especially RRSIG queries
Caveat Upgrade within same minor branch is generally low-risk; review ISC BIND 9 Release Notes for any configuration or behavior changes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Bind Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-3736 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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