{"id":"CVE-2021-20591","aliases":["EUVD-2021-8009","GHSA-mhpv-hfp2-2648"],"status":"published","title":"Uncontrolled Resource Consumption vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU...","description":"Uncontrolled Resource Consumption vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU modules (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) allows a remote unauthenticated attacker to prevent legitimate clients from connecting to the MELSOFT transmission port (TCP/IP) by not closing a connection properly, which may lead to a denial of service (DoS) condition.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-10","score":0.01497,"percentile":0.74431,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-400"],"published":"2021-06-11T15:52:45Z","modified":"2026-06-17T03:34:04Z","products":[{"vendor":"mitsubishi electric corporation","product":"melsec iq-r series cpu modules"},{"vendor":"mitsubishielectric","product":"r00cpu_firmware"},{"vendor":"mitsubishielectric","product":"r01cpu_firmware"},{"vendor":"mitsubishielectric","product":"r02cpu_firmware"},{"vendor":"mitsubishielectric","product":"r04cpu_firmware"},{"vendor":"mitsubishielectric","product":"r08cpu_firmware"},{"vendor":"mitsubishielectric","product":"r08pcpu_firmware"},{"vendor":"mitsubishielectric","product":"r08psfcpu_firmware"},{"vendor":"mitsubishielectric","product":"r08sfcpu_firmware"},{"vendor":"mitsubishielectric","product":"r120cpu_firmware"},{"vendor":"mitsubishielectric","product":"r120pcpu_firmware"},{"vendor":"mitsubishielectric","product":"r120psfcpu_firmware"},{"vendor":"mitsubishielectric","product":"r120sfcpu_firmware"},{"vendor":"mitsubishielectric","product":"r16cpu_firmware"},{"vendor":"mitsubishielectric","product":"r16pcpu_firmware"},{"vendor":"mitsubishielectric","product":"r16psfcpu_firmware"},{"vendor":"mitsubishielectric","product":"r16sfcpu_firmware"},{"vendor":"mitsubishielectric","product":"r32cpu_firmware"},{"vendor":"mitsubishielectric","product":"r32pcpu_firmware"},{"vendor":"mitsubishielectric","product":"r32psfcpu_firmware"},{"vendor":"mitsubishielectric","product":"r32sfcpu_firmware"}],"references":[{"url":"https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-003_en.pdf","tags":["x_refsource_MISC","x_transferred","Vendor Advisory"]},{"url":"https://jvn.jp/vu/JVNVU98060539/index.html","tags":["x_refsource_MISC","x_transferred","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-20591"},{"url":"https://github.com/advisories/GHSA-mhpv-hfp2-2648"}],"sources":{"cve":[{"id":"CVE-2021-20591","description":"Uncontrolled Resource Consumption vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU modules (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) allows a remote unauthenticated attacker to prevent legitimate clients from connecting to the MELSOFT transmission port (TCP/IP) by not closing a connection properly, which may lead to a denial of service (DoS) condition.","status":"published","published":"2021-06-11T15:52:45Z","modified":"2024-08-03T17:45:44.388Z","updated_at":"2026-11-02T14:32:55.19484Z"}],"euvd":[{"id":"EUVD-2021-8009","description":"Uncontrolled Resource Consumption vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU modules (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) allows a remote unauthenticated attacker to prevent legitimate clients from connecting to the MELSOFT transmission port (TCP/IP) by not closing a connection properly, which may lead to a denial of service (DoS) condition.","status":"published","published":"2021-06-11T15:52:45Z","modified":"2024-08-03T17:45:44Z","updated_at":"2026-11-03T03:25:08.888273Z"}],"ghsa":[{"id":"GHSA-mhpv-hfp2-2648","title":"Uncontrolled Resource Consumption vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU...","description":"Uncontrolled Resource Consumption vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU modules (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) allows a remote unauthenticated attacker to prevent legitimate clients from connecting to the MELSOFT transmission port (TCP/IP) by not closing a connection properly, which may lead to a denial of service (DoS) condition.","status":"published","published":"2022-05-24T19:05:05Z","modified":"2023-01-29T05:07:00Z","cwes":["CWE-400"],"updated_at":"2026-11-02T14:46:08.233339Z"}],"nvd":[{"id":"CVE-2021-20591","description":"Uncontrolled Resource Consumption vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU modules (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) allows a remote unauthenticated attacker to prevent legitimate clients from connecting to the MELSOFT transmission port (TCP/IP) by not closing a connection properly, which may lead to a denial of service (DoS) condition.","status":"published","published":"2021-06-11T16:15:08.987Z","modified":"2026-06-17T03:34:04.68Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"},{"version":"2.0","score":7.8,"vector":"AV:N/AC:L/Au:N/C:N/I:N/A:C","level":"high","assessor":"primary"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T14:06:54.439974Z"}]}}