CVE-2023-40709
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 adversary could crash the entire device by sending a large quantity of ICMP requests if the controller has the built-in web server enabled but does not have the built-in web server completely set up and configured for the SNAP PAC S1 Firmware version R10.3b
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 confidenceA denial-of-service vulnerability in SNAP PAC S1 Firmware R10.3b allows an unauthenticated attacker to crash the entire device by sending a large quantity of ICMP requests. The vulnerability is triggered specifically when the built-in web server is enabled but not fully configured, exposing an ICMP handling weakness that can be exploited to cause a complete device outage.
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= r10.3bCVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify the device modelAccess the device console or management interface and verify the model is Opto22 Snap Pac S1. This may be visible in the device status page or via SNMP/sysinfo queries.Affected if Device is not a Snap Pac S1 model - not affected by this CVE
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Check firmware versionQuery the device's firmware version through its web interface, console, or management API. Look for a version string matching exactly 'r10.3b'.Affected if Firmware version is anything other than r10.3b - not affected by this CVE
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Verify built-in web server is enabledAccess the device configuration settings and check the status of the built-in web server. This is typically found under Network Settings, Web Server, or HTTP Server configuration options.Affected if Web server is disabled - the vulnerability cannot be triggered as it requires the web server to be enabled
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Confirm web server is not fully configuredReview the web server configuration to determine if it lacks complete setup - for example, missing admin credentials, incomplete SSL/TLS setup, or missing required service parameters that would indicate a fully configured state.Affected if Web server is fully configured with all required parameters set - the specific vulnerable condition is not present
A user is affected only if they have an Opto22 Snap Pac S1 running exactly firmware r10.3b with the built-in web server enabled but not fully configured, as the vulnerability requires this specific combination to be triggered by ICMP requests.
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 dataEnsure the built-in web server is either fully configured or disabled if not needed, and apply any available firmware updates from the vendor to address the ICMP handling vulnerability.
- Consultation4.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2023-40709 — 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-2023-40709 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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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.
- 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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