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Reachable AssertionWeakness · CWE-617

CVE-2024-4076

HIGH · 7.5 CVSS v3.1 Published 2024-07-23
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
Client queries that trigger serving stale data and that also require lookups in local authoritative zone data may result in an assertion failure. This issue affects BIND 9 versions 9.16.13 through 9.16.50, 9.18.0 through 9.18.27, 9.19.0 through 9.19.24, 9.11.33-S1 through 9.11.37-S1, 9.16.13-S1 through 9.16.50-S1, and 9.18.11-S1 through 9.18.27-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 · moderate confidence

In BIND 9, client queries that trigger serving stale DNS data while simultaneously requiring lookups in local authoritative zone data can cause an assertion failure, resulting in a denial of service (server crash). The vulnerability requires stale data serving to be enabled and the query to need local authoritative zone lookups.

MitigationDisable stale data serving if not required, or update to a patched BIND 9 version once available. Consider implementing query rate limiting as a defensive measure.

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

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 'bind -v' to display the installed BIND version number
    Affected if The installed version falls within the vulnerable range of BIND 9 releases (compare your version to the affected releases)
  2. Locate BIND 9 configuration file
    Common locations are /etc/named.conf, /etc/bind/named.conf, or check the init script for the config path using 'ps aux | grep named'
    Affected if A configuration file exists indicating BIND 9 is in use
  3. Verify stale data serving is enabled
    Search the configuration file for 'stale-cache-enable yes' or 'stale-answer-enable yes' directives within the 'options' block or view configuration
    Affected if Stale data serving is explicitly enabled in the configuration
  4. Check for local authoritative zones
    Review the configuration for 'zone' statements defining local authoritative zones (type master or type slave with local file storage)
    Affected if Local authoritative zones are defined in the configuration
  5. Confirm query path exists
    Test with 'dig' or 'host' commands querying the local authoritative zones to confirm the server responds to those queries
    Affected if Queries to local authoritative zones are processed by the server

The environment is affected only if running a vulnerable BIND 9 version AND stale data serving is enabled AND local authoritative zones are configured, as all three conditions must be present for the assertion failure to occur.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Disable stale data serving if not required, or update to a patched BIND 9 version once available. Consider implementing query rate limiting as a defensive measure.

Recommended fix High confidence

BIND 9.16.51, 9.18.28, 9.19.25, or later (or corresponding S1 preview channel versions)

  1. 1. Identify the currently installed BIND 9 version using: `named -v` or `bind -v`
  2. 2. Based on the affected version range, determine the appropriate upgrade path: for 9.16.x upgrade to 9.16.51 or later, for 9.18.x upgrade to 9.18.28 or later, for 9.19.x upgrade to 9.19.25 or later
  3. 3. For supported preview (S1) versions: upgrade 9.11.37-S1 to 9.11.38-S1 or later, upgrade 9.16.50-S1 to 9.16.51-S1 or later, upgrade 9.18.27-S1 to 9.18.28-S1 or later
  4. 4. Obtain the fixed BIND 9 version from your distribution's package manager or from ISC: https://www.isc.org/download/
  5. 5. Update the package repository and install the fixed version: `apt-get update && apt-get install bind9` or `yum update bind` or equivalent for your OS
  6. 6. Restart the named service: `systemctl restart named` or `service named restart`
  7. 7. Verify the fix is applied by checking the new version: `named -v`
Caveat Standard minor version upgrade within same major series; should not introduce breaking changes but test in non-production environment first

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,280
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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-2024-4076 in production — separate from our analysis above.

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What this is

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