CVE-2020-5656
Improper access control vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R...
Improper access control 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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
Improper access control 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.
- Record
CVE-2020-5656- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Updated
- 2026-11-02
CVE List No score
Improper access control 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.
- Record
CVE-2020-5656- Updated
- 2026-11-02
EUVDEUVD-2020-26817 No score
Improper access control 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.
- Record
EUVD-2020-26817- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-f9w6-p56j-vxgh No score
Improper access control vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R...
Improper access control 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.
- Record
GHSA-f9w6-p56j-vxgh- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-5656 is a critical vulnerability (CVSS 9.8) in Mitsubishi Electric Corporation Melsec Iq-r Series, published October 30, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.97%, the 87th percentile. No source names a fixed version.