CVE-2023-23451
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 · uneditedThe Flexi Classic and Flexi Soft Gateways SICK UE410-EN3 FLEXI ETHERNET GATEW. with serial number <=2311xxxx all Firmware versions, SICK UE410-EN1 FLEXI ETHERNET GATEW. with serial number <=2311xxxx all Firmware versions, SICK UE410-EN3S04 FLEXI ETHERNET GATEW. with serial number <=2311xxxx all Firmware versions, SICK UE410-EN4 FLEXI ETHERNET GATEW. with serial number <=2311xxxx all Firmware versions, SICK FX0-GENT00000 FLEXISOFT EIP GATEW. with serial number <=2311xxxx with Firmware <=V2.11.0, SICK FX0-GMOD00000 FLEXISOFT MOD GATEW. with serial number <=2311xxxx with Firmware <=V2.11.0, SICK FX0-GPNT00000 FLEXISOFT PNET GATEW. with serial number <=2311xxxx with Firmware <=V2.12.0, SICK FX0-GENT00030 FLEXISOFT EIP GATEW.V2 with serial number <=2311xxxx all Firmware versions, SICK FX0-GPNT00030 FLEXISOFT PNET GATEW.V2 with serial number <=2311xxxx all Firmware versions and SICK FX0-GMOD00010 FLEXISOFT MOD GW with serial number <=2311xxxx with Firmware <=V2.11.0 all have Telnet enabled by factory default. No password is set in the default configuration.
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 confidenceMultiple SICK Flexi Classic and Flexi Soft Ethernet gateway devices have Telnet service enabled by factory default with no password configured. This allows unauthenticated remote attackers to potentially access the device management interface via Telnet on the exposed network service.
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 dataall versionsall versionsall versionsall versions<= 2.11.0<= 2.11.0<= 2.12.0all versionsCVSS 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 checksWork through these to decide whether this CVE applies to you.
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Scan for open Telnet portPerform a network port scan targeting the device IP address to check if TCP port 23 (Telnet) is open and listening. Use tools like nmap: nmap -p 23 <device-ip>Affected if Port 23 is open and responding on the device
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Verify Telnet access requires authenticationAttempt a Telnet connection to the device: telnet <device-ip>. Observe whether the connection grants immediate access to a management prompt or requires a username/password.Affected if Connection grants immediate access to a management interface without prompting for credentials
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Check device management interface for Telnet statusLog into the device web interface or management console and navigate to Network Services, Communication Settings, or similar configuration section. Look for Telnet service enable/disable status.Affected if Telnet service is shown as enabled in the device configuration
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Identify device model and firmware versionAccess the device web interface, management console, or use SNMP/sysinfo queries to determine the exact model number (e.g., UE410-EN3, FX0-GENT00000) and firmware version.Affected if Device model matches one of the affected products listed in the CVE and firmware version falls within the affected ranges
The device is affected if Telnet port 23 is open and accessible, especially if it provides unauthenticated access to a management interface without requiring login credentials.
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 dataDisable the Telnet service on affected devices if not required for operations. If Telnet is necessary, configure strong authentication immediately. Apply network segmentation to restrict access to management interfaces.
- Consultation4.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-23451 — 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-2023-23451 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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