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Modicon M340 Bmxp3420302 FirmwareOperating system · Schneider Electric

CVE-2020-7533

CRITICAL · 9.8 CVSS v3.1 Published 2020-12-01
Fix available
A fix is available. Upgrade to 2.10 / 3.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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
CWE-287: Improper Authentication vulnerability exists which could cause the execution of commands on the webserver without authentication when sending specially crafted HTTP requests.

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 confidence

This is a critical authentication bypass vulnerability (CWE-287) in a web application that allows unauthenticated attackers to execute arbitrary commands on the server by sending specially crafted HTTP requests. The vulnerability stems from improper or missing authentication checks on certain endpoints, allowing attackers to bypass the entire authentication mechanism.

MitigationApply vendor-provided patches immediately. If no patch exists, implement authentication checks on all HTTP request handlers and validate session tokens before allowing any command execution. Restrict network access to the web interface and deploy a WAF as a compensating control.

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 M340 Bmxp3420302 FirmwareOperating system
Affected:< 3.20
Modicon M340 Bmxp342000 FirmwareOperating system
Affected:< 3.20
Modicon M340 Bmxp341000 FirmwareOperating system
Affected:< 3.20
Modicon M340 Bmxp3420102 FirmwareOperating system
Affected:< 3.20
Bmxnoe0100 FirmwareOperating system
Affected:< 3.3
Bmxnoe0110 FirmwareOperating system
Affected:< 6.5
Bmxnoc0401 FirmwareOperating system
Affected:< 2.10
Tsxp574634 FirmwareOperating system
Affected:< 6.1

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
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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the exact model number
    Locate the product model label on the physical device or in the system documentation. Confirm it matches one of: Bmxp3420302, Bmxp342000, Bmxp341000, Bmxp3420102, Bmxnoe0100, Bmxnoe0110, Bmxnoc0401, or Tsxp574634.
    Affected if The model is NOT one of these eight listed products, then this CVE does not apply.
  2. Check the installed firmware version
    Access the device management interface or use the vendor's configuration software to retrieve the current firmware version. Compare it against the affected ranges: M340 models need version < 3.20, Bmxnoe0100 needs < 3.3, Bmxnoe0110 needs < 6.5, Bmxnoc0401 needs < 2.10, Tsxp574634 needs < 6.1.
    Affected if The firmware version falls within or below the affected version ranges listed.
  3. Verify if the web interface is enabled
    Check the device network configuration settings to determine whether the embedded web server or HTTP management interface is currently active and accessible.
    Affected if The web interface is enabled and reachable over the network.
  4. Confirm authentication is not bypassed
    Review the web service configuration for any settings that disable or skip authentication checks on HTTP request handlers. Look for any documented or undocumented endpoints that may not require credentials.
    Affected if Authentication can be bypassed or is missing on certain endpoints.

You are affected if your device model matches one of the eight listed products, runs a firmware version below the specified thresholds, and has the web interface enabled.

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.

dbcve · scoped
Upgrade available Upgrade to 2.10 / 3.3 / 3.20 or later
Fixed in 2.103.33.20
Interim mitigation

Apply vendor-provided patches immediately. If no patch exists, implement authentication checks on all HTTP request handlers and validate session tokens before allowing any command execution. Restrict network access to the web interface and deploy a WAF as a compensating control.

Recommended fix High confidence

Modicon M340 Bmxp3420302/342000/341000/3420102: upgrade to Firmware >= 3.20 | Bmxnoe0100: upgrade to Firmware >= 3.3 | Bmxnoe0110: upgrade to Firmware >= 6.5 | Bmxnoc0401: upgrade to Firmware >= 2.10 | Tsxp574634: upgrade to Firmware >= 6.1

  1. 1. Identify the exact model number and current firmware version of the affected Modicon M340 or network module device
  2. 2. Download the appropriate firmware update from the official Schneider Electric download portal (download.schneider-electric.com) or support site (www.se.com)
  3. 3. Review the firmware release notes to ensure compatibility with your specific PLC configuration and any dependent systems
  4. 4. Create a full backup of the PLC program and configuration before performing the firmware update
  5. 5. Establish a direct, wired Ethernet connection to the PLC for firmware upload (avoid wireless connections)
  6. 6. Use Schneider Electric's official firmware update tool or Unity Pro/Control Expert programming software to upload the new firmware
  7. 7. Verify the firmware version has been successfully updated by checking the device web interface or programming software
  8. 8. Test that the webserver authentication is now properly enforced and cannot be bypassed with specially crafted HTTP requests
Caveat Firmware updates on industrial PLCs may affect running programs or require re-validation of control logic; test thoroughly in a non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Modicon M340 Bmxp3420302 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2020-7533 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