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CVE-2021-20826

• Severity: high (CVSS 7.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-12-24 · updated 2026-06-17
• Weakness: CWE-522

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.

Affected products

• Idec Data File Manager: through 2.12.1
• Idec Microsmart Fc6A Firmware: through 2.32
• Idec Microsmart Plus Fc6A Firmware: through 1.91
• Idec Windedit: through 1.3.1
• IDEC Corporation WindLDR: through 8.19.1

References

• https://jvn.jp/en/vu/JVNVU92279973/index.html
• https://www.idec.com/home/lp/pdf/2021-12-24-PLC.pdf
• https://jvn.jp/en/vu/JVNVU92279973/index.html
• https://www.idec.com/home/lp/pdf/2021-12-24-PLC.pdf

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