VulnerabilityModified

CVE-2021-20596

HIGH 7.5EPSS 2.17%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (2.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

NULL Pointer Dereference in MELSEC-F Series FX3U-ENET firmware version 1.14 and prior, FX3U-ENET-L firmware version 1.14 and prior and FX3U-ENET-P502 firmware version 1.14 and prior allows a remote unauthenticated attacker to cause a DoS condition in communication by sending specially crafted packets. Control by MELSEC-F series PLC is not affected and system reset is required for recovery.

CVSS 3.1: 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 2.17% probability · 82th percentile
Public exploits: None in Exploit-DB
CISA KEV: Not listed
Weakness: CWE-476
Affected: mitsubishielectric/fx3u-enet-l firmware · mitsubishielectric/fx3u-enet-p502 firmware · mitsubishielectric/fx3u-enet firmware
Source: Mitsubishielectric.Psirt@yd.MitsubishiElectric.co.jp

EPSS trend

EPSS 2.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

https://jvn.jp/vu/JVNVU94348759/index.htmlPatch, Third Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-201-01Third Party Advisory
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-006_en.pdfPatch, Vendor Advisory
https://jvn.jp/vu/JVNVU94348759/index.htmlPatch, Third Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-201-01Third Party Advisory
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-006_en.pdfPatch, Vendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.