What’s Vulnerable › Vulnerabilities

CVE-2021-27477

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-07-01 · updated 2026-06-17
• Weakness: CWE-119

Description

When JTEKT Corporation TOYOPUC PLC versions PC10G-CPU, 2PORT-EFR, Plus CPU, Plus EX, Plus EX2, Plus EFR, Plus EFR2, Plus 2P-EFR, PC10P-DP, PC10P-DP-IO, Plus BUS-EX, Nano 10GX, Nano 2ET,PC10PE, PC10PE-16/16P, PC10E, FL/ET-T-V2H, PC10B,PC10B-P, Nano CPU, PC10P, and PC10GE receive an invalid frame, the outside area of a receive buffer for FL-net are overwritten. As a result, the PLC CPU detects a system error, and the affected products stop.

Affected products

• Jtekt 2Port-Efr Firmware: before 1.50 — fixed in 1.50
• Jtekt Fl/Et-T-V2H Firmware: before f2.8_e1.5 — fixed in f2.8_e1.5
• Jtekt Nano 10Gx Firmware: before 3.00 — fixed in 3.00
• Jtekt Nano 2Et Firmware: before 2.40 — fixed in 2.40
• Jtekt Nano Cpu Firmware: before 2.08 — fixed in 2.08
• Jtekt Pc10B-P Firmware: before 1.11 — fixed in 1.11
• Jtekt Pc10B Firmware: before 1.11 — fixed in 1.11
• Jtekt Pc10E Firmware: before 1.02 — fixed in 1.02
• Jtekt Pc10G-Cpu Firmware: before 3.91 — fixed in 3.91
• Jtekt Pc10Ge Firmware: before 1.04 — fixed in 1.04
• Jtekt Pc10P-Dp-Io Firmware: before 1.50 — fixed in 1.50
• Jtekt Pc10P-Dp Firmware: before 1.50 — fixed in 1.50
• Jtekt Pc10P Firmware: before 1.05 — fixed in 1.05
• Jtekt Pc10Pe-16/16P Firmware: before 1.02 — fixed in 1.02
• Jtekt Pc10Pe Firmware: before 1.02 — fixed in 1.02
• Jtekt Plus 2P-Efr Firmware: before 3.11 — fixed in 3.11
• Jtekt Plus Bus-Ex Firmware: before 2.13 — fixed in 2.13
• Jtekt Plus Cpu Firmware: before 3.11 — fixed in 3.11
• Jtekt Plus Efr2 Firmware: before 3.11 — fixed in 3.11
• Jtekt Plus Efr Firmware: before 3.11 — fixed in 3.11
• Jtekt Plus Ex2 Firmware: before 3.11 — fixed in 3.11
• Jtekt Plus Ex Firmware: before 3.11 — fixed in 3.11

How to fix

Upgrade to a fixed version: Jtekt 2Port-Efr Firmware 1.50; Jtekt Fl/Et-T-V2H Firmware f2.8_e1.5; Jtekt Nano 10Gx Firmware 3.00; Jtekt Nano 2Et Firmware 2.40; Jtekt Nano Cpu Firmware 2.08; Jtekt Pc10B-P Firmware 1.11; Jtekt Pc10B Firmware 1.11; Jtekt Pc10E Firmware 1.02; Jtekt Pc10G-Cpu Firmware 3.91; Jtekt Pc10Ge Firmware 1.04; Jtekt Pc10P-Dp-Io Firmware 1.50; Jtekt Pc10P-Dp Firmware 1.50. Check the vendor advisory for mitigations.

References

• https://us-cert.cisa.gov/ics/advisories/icsa-21-180-04
• https://us-cert.cisa.gov/ics/advisories/icsa-21-180-04

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