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Rewterz Threat Advisory – CVE-2021-20591 – ICS: Mitsubishi Electric MELSEC iQ-R Series

Severity

Medium

Analysis Summary

CVE-2021-20591

The MELSEX iQ-R Series vulnerability allows an attacker to prevent legitimate clients from connecting to an affected product by manipulating the link parameter or changing its state. This is due to improper session management. However, if multiple MELSOFT transmission ports (TCP/IP) are open, the other ports are not affected. Sequence control is not affected by this vulnerability.

Impact

  • Denial of Service

Affected Vendors

Mitsubishi Electric

Affected Products

  • R00/01/02CPU: All versions
  • R04/08/16/32/120(EN)CPU: All versions
  • R08/16/32/120SFCPU: All versions
  • R08/16/32/120PCPU: All versions
  • R08/16/32/120PSFCPU: All versions

Remediation

Refer to vendor advisory for the complete list of affected products and their respective patches at https://us-cert.cisa.gov/ics/advisories/icsa-21-147-05

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