Microsmart Fc6a FirmwareOperating system · Idec

CVE-2021-20826

HIGH · 7.6 CVSS v3.1 Published 2021-12-24

Fix available

A fix is available. Upgrade to after 8.19.1 or later.

See remediation →

81/100

Remediation priority · High

No privileges Zero-click

Official description

NVD · unedited

Unprotected transport of credentials vulnerability in IDEC PLCs (FC6A Series MICROSmart All-in-One CPU module v2.32 and earlier, FC6A Series MICROSmart Plus CPU module v1.91 and earlier, WindLDR v8.19.1 and earlier, WindEDIT Lite v1.3.1 and earlier, and Data File Manager v2.12.1 and earlier) allows an attacker to obtain the PLC Web server user credentials from the communication between the PLC and the software. As a result, the complete access privileges to the PLC Web server may be obtained, and manipulation of the PLC output and/or suspension of the PLC may be conducted.

Technical summary

dbcve analysis · high confidence

Credentials are transmitted in cleartext between IDEC PLCs (FC6A Series) and associated software tools (WindLDR, WindEDIT Lite, Data File Manager). An attacker intercepting this traffic can obtain PLC Web server user credentials, enabling full administrative access to manipulate PLC outputs or disrupt operations.

MitigationUpdate PLC firmware to v2.33+ (All-in-One) or v1.92+ (Plus), and software tools to versions beyond those specified. Ensure all PLC-to-software communications occur over encrypted channels or within a secured network segment.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions

NVD · CPE data

Microsmart Fc6a FirmwareOperating system

Affected:<= 2.32

Microsmart Plus Fc6a FirmwareOperating system

Affected:<= 1.91

Data File ManagerApplication

Affected:<= 2.12.1

WindeditApplication

Affected:<= 1.3.1

WindldrApplication

Affected:<= 8.19.1

CVSS breakdown

From the vector

Attack vector: Adjacent
Complexity: Low
Privileges: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: Low
Availability: Low

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

Am I affected?

dbcve checks

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

Check PLC firmware version on FC6A (All-in-One)

Access the PLC web interface and navigate to the firmware version information page, or use WindLDR to connect and read the firmware version from the PLC properties

Affected if The displayed firmware version is 2.32 or lower
Check PLC firmware version on FC6A Plus

Access the PLC web interface and navigate to the firmware version information page, or use WindLDR to connect and read the firmware version from the PLC properties

Affected if The displayed firmware version is 1.91 or lower
Check installed WindLDR version

Open WindLDR, then go to Help > About WindLDR to view the installed software version

Affected if The displayed version is 8.19.1 or lower
Check installed WindEDIT Lite version

Open WindEDIT Lite, then go to Help > About to view the installed software version

Affected if The displayed version is 1.3.1 or lower
Check installed Data File Manager version

Open Data File Manager, then go to Help > About to view the installed software version

Affected if The displayed version is 2.12.1 or lower
Inspect PLC web server access method

Verify whether the PLC web server is accessed using HTTP (non-secure) rather than HTTPS by checking the URL in the browser address bar when logging into the PLC web interface

Affected if The web interface is accessed via HTTP URL (http://) rather than HTTPS (https://)

You are affected if any PLC firmware is at or below 2.32 (All-in-One) or 1.91 (Plus), OR any software tool is at or below the specified versions, AND the PLC web server is accessed over unencrypted HTTP.

Generated from the published advisory. Verify against your own configuration.

Remediation

dbcve · scoped

Upgrade available Upgrade to a release after 8.19.1

Interim mitigation

Update PLC firmware to v2.33+ (All-in-One) or v1.92+ (Plus), and software tools to versions beyond those specified. Ensure all PLC-to-software communications occur over encrypted channels or within a secured network segment.

Recommended fix Moderate confidence

MICROSmart FC6A Firmware >2.32, MICROSmart Plus FC6A Firmware >1.91, WindLDR >8.19.1, WindEDIT Lite >1.3.1, Data File Manager >2.12.1 (obtain exact fixed versions from IDEC)

1. Identify the specific IDEC PLC product and software in use from the affected list: MICROSmart FC6A (Firmware <=2.32), MICROSmart Plus FC6A (Firmware <=1.91), WindLDR (<=8.19.1), WindEDIT Lite (<=1.3.1), or Data File Manager (<=2.12.1)
2. Visit the official IDEC support website at www.idec.com to check for available firmware/software updates
3. Download and apply the latest available firmware version for the PLC module from IDEC's official support page
4. Download and apply the latest available software version (WindLDR, WindEDIT Lite, or Data File Manager) from IDEC's official support page
5. After updating, verify that the credentials are now protected during transport by confirming the use of encryption or secure communication protocols
6. Change all PLC Web server user credentials as a precautionary measure after applying the update

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

Fix this in Microsmart Fc6a Firmware Scoped from the published advisory

Consultation4.0 h
Implementation8.0 h
Testing8.0 h
Review / QA4.0 h

24.0 hours of engineering $4,160

Get the upgrade done

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Scan for this in your stack

Free · runs locally

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References

Primary sources

www.idec.comVendor Advisory
jvn.jpThird Party Advisory
nvd.nist.govNVD record

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-20826 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2021-20826?

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

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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

At a glance

A fix existsUpgrade to after 8.19.1 or later

Severity 7.6 High

Exploit likelihood EPSS, next 30 days 0.4%

Affects: Microsmart Fc6a Firmware

Remediation

A high-priority fix

Fix this in Microsmart Fc6a Firmware 24 hrs · Moderate

Typical engagement from $4,160

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2021-20826 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References