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Modicon Tsxety4103 FirmwareOperating system · Schneider Electric

CVE-2020-7564

HIGH · 8.8 CVSS v3.1 Published 2020-11-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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
A CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability exists in the Web Server on Modicon M340, Modicon Quantum and Modicon Premium Legacy offers and their Communication Modules (see notification for details) which could cause write access and the execution of commands when uploading a specially crafted file on the controller over FTP.

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 confidence

A CWE-120 classic buffer overflow vulnerability exists in the Web Server component of Modicon M340, Modicon Quantum, and Modicon Premium PLCs and their communication modules. The vulnerability is triggered by uploading a specially crafted file over FTP, allowing an attacker to achieve write access and execute arbitrary commands on the controller.

MitigationApply vendor-supplied firmware updates to the affected Modicon controllers and communication modules. Restrict FTP access to the PLC web server to trusted networks or disable FTP if not required, and implement network segmentation to limit exposure of industrial control system devices.

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
Modicon Tsxety4103 FirmwareOperating system
Affected:all versions
Modicon Tsxety5103 FirmwareOperating system
Affected:all versions
Modicon Tsxp574634 FirmwareOperating system
Affected:all versions
Modicon Tsxp575634 FirmwareOperating system
Affected:all versions
Modicon Tsxp576634 FirmwareOperating system
Affected:all versions
Modicon Quantum 140noe77101 FirmwareOperating system
Affected:all versions
Modicon Quantum 140noe77111 FirmwareOperating system
Affected:all versions
Modicon Quantum 140noc78100 FirmwareOperating system
Affected:all versions

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/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 the PLC model and firmware version
    Access the PLC configuration software (Unity Pro or EcoStruxure Control Expert) or use the PLC's built-in web interface to retrieve the exact model number and firmware version. Compare against the list of affected products: Modicon Tsxety4103, Tsxety5103, Tsxp574634, Tsxp575634, Tsxp576634, Quantum 140noe77101, 140noe77111, 140noc78100.
    Affected if The installed PLC model matches any of the affected product codes and the firmware version falls within the affected range.
  2. Confirm FTP server is enabled on the PLC
    Use the PLC configuration software or access the device's web management interface to verify whether the FTP server feature is enabled. Look for FTP service settings in the network configuration section.
    Affected if FTP server is enabled and running on the PLC.
  3. Verify FTP write access is permitted
    Check the FTP server configuration on the PLC to determine if write permissions are granted. In the PLC network settings, examine the FTP access control configuration to see if upload/write operations are allowed.
    Affected if FTP write access is permitted, allowing file uploads to the device.
  4. Assess network exposure of the FTP service
    Review network firewall rules, VLAN configurations, or access control lists to determine if the PLC's FTP port (default port 21) is accessible from networks outside the trusted control system network segment.
    Affected if The FTP service on the PLC is reachable from untrusted or external networks.

The environment is affected if the PLC model matches one of the affected Modicon products and FTP with write access is enabled and accessible, regardless of firmware version since all versions are vulnerable.

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

Apply vendor-supplied firmware updates to the affected Modicon controllers and communication modules. Restrict FTP access to the PLC web server to trusted networks or disable FTP if not required, and implement network segmentation to limit exposure of industrial control system devices.

Fix this in Modicon Tsxety4103 Firmware Scoped from the published advisory
  • Consultation5.0 h
  • Implementation10.0 h
  • Testing6.0 h
  • Review / QA3.0 h
24.0 hours of engineering $4,240
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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-2020-7564 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data