CVE-2025-41704
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 · uneditedAn unauthanticated remote attacker can perform a DoS of the Modbus service by sending a specific function and sub-function code without affecting the core functionality.
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 confidenceAn unauthenticated remote attacker can cause denial of service of the Modbus service by sending a specific function and sub-function code combination. The attack does not affect core system functionality, indicating the vulnerability is isolated to the Modbus protocol implementation.
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
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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 checksWork through these to decide whether this CVE applies to you.
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Confirm Modbus service is exposedIdentify systems running Modbus (TCP/UDP port 502, or serial) by reviewing network scans, firewall rules, and running services. Check for Modbus-enabled devices on the network.Affected if Modbus service is listening and accessible on the network
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Identify Modbus software/device versionQuery the Modbus device or software for its firmware/software version using vendor-specific tools, SNMP, or by accessing the device management interface. Compare the installed version against any available vendor advisory or version information.Affected if Version is older than the fixed release (if vendor has published one)
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Verify function code configurationAccess the Modbus device or software configuration and review which Modbus function codes are enabled. Common function codes include 1-4 (read), 5-6 (write), 15-16 (bulk write). Check if the device allows restricting or disabling specific function codes.Affected if Specific function/sub-function codes causing the DoS are not disabled or restricted
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Check if unauthenticated access is allowedReview Modbus access controls to determine if authentication, IP filtering, or other access restrictions are required. Attempt a Modbus connection without credentials if authorized.Affected if Unauthenticated access to Modbus is permitted and the service is network-accessible
If a Modbus service is exposed on the network and the specific function/sub-function codes causing the DoS are not disabled or restricted, the environment is affected by this vulnerability.
Generated from the published advisory. Verify against your own configuration.
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 dataImplement input validation or filtering for the specific function/sub-function codes causing the DoS, or disable unused Modbus function codes in the device configuration. Consider adding rate limiting on Modbus connections as a defense-in-depth measure.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-41704 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-41704 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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