CVE-2021-20613

highpriority · track · 31EPSS 0.036 · 89 %ileEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

3.60% (89th) EPSS

CVSS 7.8 · high

Is it mine?

10 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · cisa_csaf_ot · nvd

EPSS · scored 2026-10-27

Improper initialization vulnerability in MELSEC-F series FX3U-ENET Firmware version 1.16 and prior, FX3U-ENET-L Firmware version 1.16 and prior and FX3U-ENET-P502 Firmware version 1.16 and prior allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition in communication function of the product by sending specially crafted packets. Control by MELSEC-F series PLC is not affected by this vulnerability, but system reset is required for recovery.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedFX3U-ENETcisa_csaf_ot
FX3U-ENET-P502: Firmware Version 1.17 or later
FixedFX3U-ENET-Lcisa_csaf_ot
FX3U-ENET-P502: Firmware Version 1.17 or later
FixedFX3U-ENET-P502cisa_csaf_ot
FX3U-ENET-P502: Firmware Version 1.17 or later
MitigationFX3U-ENETcisa_csaf_ot
FX3U-ENET-L: Firmware Version 1.17 or later
MitigationFX3U-ENET-Lcisa_csaf_ot
FX3U-ENET-L: Firmware Version 1.17 or later
MitigationFX3U-ENET-P502cisa_csaf_ot
FX3U-ENET-L: Firmware Version 1.17 or later

cvss

Technical severity, 0–10. One row per scoring source.

7.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–7.8

v2.07.8highAV:N/AC:L/Au:N/C:N/I:N/A:Cprimary · NVD / NIST USexploitability 10 · impact 6.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.07.5highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · CISA US

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-665USprimaryCWE-665US

affected products (10)

Products and version ranges known to be affected.

FX3U-ENET-L: Firmware Version 1.16 and priorall versionscisa_csaf_otUS
FX3U-ENET-P502: Firmware Version 1.16 and priorall versionscisa_csaf_otUS
FX3U-ENET: Firmware Version 1.16 and priorall versionscisa_csaf_otUS
Mitsubishi Electric FX3U-ENET≤ 1.16cisa_csaf_otUS
Mitsubishi Electric FX3U-ENET-L≤ 1.16cisa_csaf_otUS
Mitsubishi Electric FX3U-ENET-P502≤ 1.16cisa_csaf_otUS
n/a MELSEC-F series FX3U-ENET; MELSEC-F series FX3U-ENET-L; MELSEC-F series FX3U-ENET-P502≤ Firmware version 1.16 and priorenisa_euvdEU
mitsubishielectric fx3u-enet firmware≤ 1.16nvdUScpe:2.3:o:mitsubishielectric:fx3u-enet_firmware:*:*:*:*:*:*:*:*
mitsubishielectric fx3u-enet-l firmware≤ 1.16nvdUScpe:2.3:o:mitsubishielectric:fx3u-enet-l_firmware:*:*:*:*:*:*:*:*
mitsubishielectric fx3u-enet-p502 firmware≤ 1.16nvdUScpe:2.3:o:mitsubishielectric:fx3u-enet-p502_firmware:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

ICSA-22-013-07Mitsubishi Electric MELSEC-F Series2022-01-13icsa · cisa_csaf_otUS
Successful exploitation of this vulnerability may cause a denial-of-service condition in the affected product.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cisa_csaf_ot nvd NVD CVE.org MITRE

published 2022-01-14modified 2026-06-17

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references (11)

External citations — patches, advisories, analysis.

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