CVE-2021-20596

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.

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.57%
Vendor Advisory mitsubishielectric.com
Affected: n/a MELSEC-F Series FX3U-ENET; FX3U-ENET-L; FX3U-ENET-P502
Published at:
Updated at:

References

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

Frequently Asked Questions

What is the severity of CVE-2021-20596?
CVE-2021-20596 has been scored as a high severity vulnerability.
How to fix CVE-2021-20596?
To fix CVE-2021-20596, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-20596 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-20596 is being actively exploited. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-20596?
CVE-2021-20596 affects n/a MELSEC-F Series FX3U-ENET; FX3U-ENET-L; FX3U-ENET-P502.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.