CVE-2021-20596

7.5 highEPSS 2.2%

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.

Severity

CVSS 3.1

7.5 high

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 2.2% chance of exploitation in the next 30 days; higher than 82% of CVEs (scores of 2026-10-31)
CWE: CWE-476
Published: 2021-07-22
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

mitsubishielectric:fx3u-enet-l_firmware
mitsubishielectric:fx3u-enet-p502_firmware
mitsubishielectric:fx3u-enet_firmware

References

https://jvn.jp/vu/JVNVU94348759/index.html
https://us-cert.cisa.gov/ics/advisories/icsa-21-201-01
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-006_en.pdf
https://jvn.jp/vu/JVNVU94348759/index.html
https://us-cert.cisa.gov/ics/advisories/icsa-21-201-01

Check your stack JSON