What’s Vulnerable › Vulnerabilities

CVE-2021-20609

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-12-01 · updated 2026-06-17
• Weakness: CWE-400

Description

Uncontrolled Resource Consumption vulnerability in Mitsubishi Electric MELSEC iQ-R Series R00/01/02CPU, MELSEC iQ-R Series R04/08/16/32/120(EN)CPU, MELSEC iQ-R Series R08/16/32/120SFCPU, MELSEC iQ-R Series R08/16/32/120PCPU, MELSEC iQ-R Series R08/16/32/120PSFCPU, MELSEC iQ-R Series R16/32/64MTCPU, MELSEC iQ-R Series R12CCPU-V, MELSEC Q Series Q03UDECPU, MELSEC Q Series Q04/06/10/13/20/26/50/100UDEHCPU, MELSEC Q Series Q03/04/06/13/26UDVCPU, MELSEC Q Series Q04/06/13/26UDPVCPU, MELSEC Q Series Q12DCCPU-V, MELSEC Q Series Q24DHCCPU-V(G), MELSEC Q Series Q24/26DHCCPU-LS, MELSEC Q Series MR-MQ100, MELSEC Q Series Q172/173DCPU-S1, MELSEC Q Series Q172/173DSCPU, MELSEC Q Series Q170MCPU, MELSEC Q Series Q170MSCPU(-S1), MELSEC L Series L02/06/26CPU(-P), MELSEC L Series L26CPU-(P)BT and MELIPC Series MI5122-VW allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition by sending specially crafted packets. System reset is required for recovery.

Affected products

• Mitsubishi Melipc Mi5122-Vw Firmware: all versions
• Mitsubishi Melsec Iq-R R00 Cpu Firmware: through 24
• Mitsubishi Melsec Iq-R R01 Cpu Firmware: through 24
• Mitsubishi Melsec Iq-R R02 Cpu Firmware: through 24
• Mitsubishi Melsec Iq-R R04 Cpu Firmware: through 57
• Mitsubishi Melsec Iq-R R04 Pcpu Firmware: through 29
• Mitsubishi Melsec Iq-R R08 Cpu Firmware: through 57
• Mitsubishi Melsec Iq-R R08 Pcpu Firmware: through 29
• Mitsubishi Melsec Iq-R R08 Sfcpu Firmware: all versions
• Mitsubishi Melsec Iq-R R120 Cpu Firmware: through 57
• Mitsubishi Melsec Iq-R R120 Pcpu Firmware: through 29
• Mitsubishi Melsec Iq-R R120 Sfcpu Firmware: all versions
• Mitsubishi Melsec Iq-R R12 Ccpu-V Firmware: all versions
• Mitsubishi Melsec Iq-R R16 Cpu Firmware: through 57
• Mitsubishi Melsec Iq-R R16 Mtcpu Firmware: all versions
• Mitsubishi Melsec Iq-R R16 Pcpu Firmware: through 29
• Mitsubishi Melsec Iq-R R16 Sfcpu Firmware: all versions
• Mitsubishi Melsec Iq-R R32 Cpu Firmware: through 57
• Mitsubishi Melsec Iq-R R32 Mtcpu Firmware: all versions
• Mitsubishi Melsec Iq-R R32 Pcpu Firmware: through 29
• Mitsubishi Melsec Iq-R R32 Sfcpu Firmware: all versions
• Mitsubishi Melsec Iq-R R64 Mtcpu Firmware: all versions
• Mitsubishi Melsec L02Cpu(-P) Firmware: all versions
• Mitsubishi Melsec L06Cpu(-P) Firmware: all versions
• Mitsubishi Melsec L26Cpu(-P) Firmware: all versions
• Mitsubishi Melsec L26Cpu-(P)Bt Firmware: all versions
• Mitsubishi Melsec Mr-Mq100 Firmware: all versions
• Mitsubishi Melsec Q03Udecpu Firmware: all versions
• Mitsubishi Melsec Q03Udvcpu Firmware: all versions
• Mitsubishi Melsec Q04Udecpu Firmware: all versions

References

• https://jvn.jp/vu/JVNVU94434051/index.html
• https://us-cert.cisa.gov/ics/advisories/icsa-21-334-02
• https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-019_en.pdf
• https://jvn.jp/vu/JVNVU94434051/index.html
• https://us-cert.cisa.gov/ics/advisories/icsa-21-334-02
• https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-019_en.pdf

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