CVE-2017-16723
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 · uneditedA Cross-site Scripting issue was discovered in PHOENIX CONTACT FL COMSERVER BASIC 232/422/485, FL COMSERVER UNI 232/422/485, FL COMSERVER BAS 232/422/485-T, FL COMSERVER UNI 232/422/485-T, FL COM SERVER RS232, FL COM SERVER RS485, and PSI-MODEM/ETH (running firmware versions prior to 1.99, 2.20, or 2.40). The cross-site scripting vulnerability has been identified, which may allow remote code execution.
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 confidenceA cross-site scripting (XSS) vulnerability in the web interface of Phoenix Contact FL COMSERVER devices allows attackers to inject malicious JavaScript code through unsanitized input fields. This can lead to session hijacking, credential theft, and potentially remote code execution via browser-based attacks.
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= 2.40= 2.40= 2.40= 1.99= 1.99= 2.20= 2.40= 2.40CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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 Phoenix Contact FL COMSERVER or PSI Modem devices on your networkReview network documentation or scan your network for devices with vendor identifier 'Phoenix Contact' and product names containing 'FL COMSERVER', 'COM SERVER', or 'PSI MODEM'Affected if Device model is any of: FL COMSERVER Basic 232, FL COMSERVER Uni 422, FL COMSERVER Bas 485 T, FL COM Server RS232, FL COM Server RS485, PSI Modem/Eth, FL COMSERVER Basic 422, or FL COMSERVER Basic 485
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Determine installed firmware versionAccess the device web interface and navigate to the System Information or Status page, or use the device's management console or configuration tool to retrieve the firmware versionAffected if Firmware version is exactly 2.40 (for COMSERVER models), 1.99 (for RS232/RS485 models), or 2.20 (for PSI Modem/Eth)
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Verify web interface is enabled and accessibleAttempt to access the device web interface via HTTP/HTTPS on the device IP address. Check device configuration settings for web interface statusAffected if Web interface is enabled and reachable on the network
Device is affected if it is a Phoenix Contact FL COMSERVER or PSI Modem model with firmware version 2.40, 1.99, or 2.20 respectively, and the web interface is enabled and accessible.
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 dataUpdate affected devices to firmware version 1.99, 2.20, or 2.40 (or later) as appropriate for the specific device model. If updates cannot be applied immediately, disable the web interface or restrict network access.
- Consultation3.0 h
- Implementation6.0 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-2017-16723 — 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-2017-16723 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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