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Improper Input ValidationWeakness · CWE-20

CVE-2024-11737

CRITICAL · 9.8 CVSS v3.1 Published 2024-12-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
CWE-20: Improper Input Validation vulnerability exists that could lead to a denial of service and a loss of confidentiality, integrity of the controller when an unauthenticated crafted Modbus packet is sent to the device.

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

A CWE-20 Improper Input Validation vulnerability in a controller's Modbus protocol implementation allows unauthenticated attackers to send crafted Modbus packets that bypass validation checks, potentially causing denial of service and compromising confidentiality and integrity of the controller.

MitigationImplement proper input validation and bounds checking on all Modbus packet fields; apply network segmentation to isolate industrial control devices and restrict Modbus access to authorized systems only.

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 if Modbus protocol is enabled on the controller
    Review the controller's configuration settings, web interface, or device documentation to determine if Modbus TCP (port 502) or Modbus RTU over TCP is actively configured and running.
    Affected if Modbus protocol is enabled and the controller is actively listening for Modbus connections on any network interface.
  2. Verify network exposure of Modbus service
    Scan the network or review firewall rules to determine if port 502 (Modbus TCP) is accessible from untrusted network segments or the internet. Use commands like 'netstat -an | grep 502' on the device or perform an external port scan.
    Affected if Port 502 is open and reachable from unauthenticated or untrusted network locations.
  3. Determine the installed firmware or software version
    Access the controller's web interface, administrative console, or use vendor-provided management tools to retrieve the current firmware or software version. Consult the device label or system information page.
    Affected if The installed version falls within any affected version range provided by the vendor for this CVE, or if the version cannot be determined and Modbus is enabled.
  4. Check for Modbus packet filtering or validation controls
    Review the controller's security settings, access control lists, or intrusion detection logs to determine if any input validation or packet filtering is applied to Modbus traffic before processing.
    Affected if No explicit input validation or packet validation controls are configured for incoming Modbus requests.
  5. Confirm whether authentication is required for Modbus access
    Examine the controller's user authentication settings, Modbus connection policies, or API security configuration to verify if unauthenticated Modbus connections are permitted.
    Affected if The controller accepts Modbus connections without requiring authentication or valid credentials.

You are affected if Modbus protocol is enabled on your controller and is accessible to unauthenticated attackers on the network, and your installed version matches the affected range or cannot be verified against known patched versions.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement proper input validation and bounds checking on all Modbus packet fields; apply network segmentation to isolate industrial control devices and restrict Modbus access to authorized systems only.

Have this fixed Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA6.0 h
42.0 hours of engineering $7,360
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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-2024-11737 in production — separate from our analysis above.

No notes yet

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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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