How severe is CVE-2021-20826?

CVE-2021-20826 has a CVSS 3.x base score of 7.6, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability low.

Is CVE-2021-20826 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20826?

CVE-2021-20826 primarily affects Idec Data File Manager. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20826?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-20826 published?

CVE-2021-20826 was published on 2021-12-24 and last updated on 2026-06-17.

CVE-2021-20826

CVE-2021-20826 is a high-severity vulnerability in Idec Data File Manager with a CVSS 3.x base score of 7.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-522.

Key facts

Severity: High (CVSS 3.x base score 7.6)
CVSS v2: 3.3
EPSS exploit prediction: 0% (31st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-522
Affected product: Idec Data File Manager
Published: 2021-12-24
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-20826?: 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.
How severe is CVE-2021-20826?: CVE-2021-20826 has a CVSS 3.x base score of 7.6, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability low.
Is CVE-2021-20826 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20826?: CVE-2021-20826 primarily affects Idec Data File Manager. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-20826?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-20826 published?: CVE-2021-20826 was published on 2021-12-24 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:o:idec:microsmart_fc6a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:idec:microsmart_plus_fc6a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:a:idec:data_file_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:idec:windedit:*:*:*:*:*:*:*:*
cpe:2.3:a:idec:windldr:*:*:*:*:*:*:*:*

More vulnerabilities in Idec Data File Manager

CVE-2021-37401 — Critical (CVSS 9.8): An attacker may obtain the user credentials from file servers, backup repositories, or ZLD files saved in SD cards. As…
CVE-2021-37400 — Critical (CVSS 9.8): An attacker may obtain the user credentials from the communication between the PLC and the software. As a result, the…
CVE-2021-20827 — High (CVSS 7.5): Plaintext storage of a password vulnerability in IDEC PLCs (FC6A Series MICROSmart All-in-One CPU module v2.32 and…

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