CVE-2020-5653

CVE-2020-5653 is a critical-severity vulnerability in Mitsubishielectric Melsec Iq-rj71eip91 Firmware with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-120.

Key facts

Description

Buffer overflow vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network Interface Module First 2 digits of serial number are '02' or before, RJ71PN92 PROFINET IO Controller Module First 2 digits of serial number are '01' or before, RD81DL96 High Speed Data Logger Module First 2 digits of serial number are '08' or before, RD81MES96N MES Interface Module First 2 digits of serial number are '04' or before, and RD81OPC96 OPC UA Server Module First 2 digits of serial number are '04' or before) allows a remote unauthenticated attacker to stop the network functions of the products or execute a malicious program via a specially crafted packet.

Frequently asked questions

What is CVE-2020-5653?
Buffer overflow vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network Interface Module First 2 digits of serial number are '02' or before, RJ71PN92 PROFINET IO Controller Module First 2 digits of serial number are '01' or before, RD81DL96 High Speed Data Logger Module First 2 digits of serial number are '08' or before, RD81MES96N MES Interface Module First 2 digits of serial number are '04' or before, and RD81OPC96 OPC UA Server Module First 2 digits of serial number are '04' or before) allows a remote unauthenticated attacker to stop the network functions of the products or execute a malicious program via a specially crafted packet.
How severe is CVE-2020-5653?
CVE-2020-5653 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-5653 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-5653?
CVE-2020-5653 primarily affects Mitsubishielectric Melsec Iq-rj71eip91 Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-5653?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-5653 published?
CVE-2020-5653 was published on 2020-11-02 and last updated on 2026-06-17.

References

Affected products (5)

More vulnerabilities in Mitsubishielectric Melsec Iq-rj71eip91 Firmware

All CVEs affecting Mitsubishielectric Melsec Iq-rj71eip91 Firmware →

Other CWE-120 (Classic Buffer Overflow) vulnerabilities

Browse all CWE-120 (Classic Buffer Overflow) vulnerabilities →