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Resource Allocation Without LimitsWeakness · CWE-770

CVE-2024-1975

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
If a server hosts a zone containing a "KEY" Resource Record, or a resolver DNSSEC-validates a "KEY" Resource Record from a DNSSEC-signed domain in cache, a client can exhaust resolver CPU resources by sending a stream of SIG(0) signed requests. This issue affects BIND 9 versions 9.0.0 through 9.11.37, 9.16.0 through 9.16.50, 9.18.0 through 9.18.27, 9.19.0 through 9.19.24, 9.9.3-S1 through 9.11.37-S1, 9.16.8-S1 through 9.16.49-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 · high confidence

A CPU exhaustion vulnerability in BIND 9 allows remote attackers to cause denial of service by sending a stream of SIG(0) signed requests targeting zones or cached data containing KEY Resource Records, leading to excessive CPU consumption on the DNS resolver.

MitigationUpgrade BIND 9 to a version beyond the affected ranges (9.11.38+, 9.16.51+, 9.18.28+, 9.19.25+, or respective S1 versions) or implement query rate limiting on affected resolvers as a temporary workaround.

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 installation and version
    Run 'named -v' or 'named -V' to display the BIND version. On Linux, also check package manager: 'rpm -q bind' or 'dpkg -l bind9'.
    Affected if The installed version is 9.11.x before 9.11.38, 9.16.x before 9.16.51, 9.18.x before 9.18.28, or 9.19.x before 9.19.25.
  2. Confirm BIND named service is running
    Run 'systemctl status named' or 'ps -ef | grep named' to verify the named process is active.
    Affected if named is running and the version matches the affected ranges.
  3. Verify recursion is enabled
    Inspect the named.conf file (typically in /etc/bind/named.conf.options or /etc/named.conf) and look for 'options { recursion yes; }' or check with 'named-checkconf -z'.
    Affected if Recursion is enabled (recursion yes;) - this is required for the vulnerability to be exploitable as the resolver must process recursive queries.
  4. Check allow-recursion or allow-query settings
    Review named.conf for 'allow-recursion' or 'allow-query' statements to determine which clients can submit recursive queries.
    Affected if The resolver accepts recursive queries from untrusted or wide-open networks (0.0.0.0/0 or lacking proper ACL restrictions).
  5. Inspect zone configurations for KEY records
    Use 'dig +short KEY <zonename>' against the resolver or review zone files for 'KEY' record types. Also check cached data with 'dig +ad +sigchase KEY <name>' if available.
    Affected if The resolver serves zones or caches data containing KEY Resource Records, which are required for the attack to trigger CPU exhaustion.

You are affected if BIND 9 is running with a version in the affected ranges AND recursion is enabled, allowing external attackers to send SIG(0) signed requests targeting zones with KEY records.

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

Upgrade BIND 9 to a version beyond the affected ranges (9.11.38+, 9.16.51+, 9.18.28+, 9.19.25+, or respective S1 versions) or implement query rate limiting on affected resolvers as a temporary workaround.

Recommended fix Moderate confidence

BIND 9.18.28 (or latest stable in your current series)

  1. 1. Identify the currently installed BIND9 version using: `named -v` or `bind -v`
  2. 2. Determine which BIND9 series you are running (9.11.x, 9.16.x, 9.18.x, or 9.19.x)
  3. 3. For BIND 9.11.x: Upgrade to version 9.11.38 or later
  4. 4. For BIND 9.16.x: Upgrade to version 9.16.51 or later
  5. 5. For BIND 9.18.x: Upgrade to version 9.18.28 or later
  6. 6. For BIND 9.19.x: Upgrade to version 9.19.25 or later (or migrate to stable 9.18.x)
  7. 7. For supported preview editions (-S1): Apply the corresponding fixed version for your series
  8. 8. After upgrade, verify the new version is running: `named -v`
Caveat Upgrading BIND may require configuration adjustments; test in non-production environment first, especially when moving between major series

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

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2024-1975 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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