CVE-2026-82784

Published Sep 14, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

Description

Missing authentication for critical function vulnerability exists in Remote I/O Coupler Unit (Server Type) CPSN-MCB271-*. An attacker may execute a REST API without authentication, which could allow the attacker to retrieve I/O values and/or control the output.

Analysis

Technical impact

An attacker can invoke critical REST API functions on the Contec Remote I/O Coupler Unit (Server Type) CPSN-MCB271-* without authentication, allowing them to read I/O values or command outputs. The vulnerability is a Missing Authentication flaw (CWE-306) and is scored with a CVSS of 6.9, indicating moderate severity and potential impacts to confidentiality, integrity and availability.

Affected Systems

The affected product is Contec Co., Ltd.'s Remote I/O Coupler Unit (Server Type) CPSN-MCB271-* - all models in the series are impacted, no specific firmware or software version is listed.

Risk and Exploitability

The EPSS score is 0.00201, indicating a very low probability of exploitation, and the vulnerability is not listed in CISA's KEV catalog, suggesting no known widespread exploitation yet; however, the CVSS of 6.9 reflects moderate risk. The flaw is exploitable remotely over the network via the exposed REST API with no authentication required. A remote attacker could potentially retrieve sensitive data or disrupt operation by manipulating I/O outputs.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Contec Co., Ltd.

Remote I/O Coupler Unit (Server Type) CPSN-MCB271-*

unaffected

Version	Status	Constraints
`0`	affected	< 1.82

No data.

Vendor Product Versions

Contec

Remote I/o Coupler Unit (server Type) Cpsn-mcb271-*

Version	Status	Scheme	Platform
`[0,1.82)`	affected	generic	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the security update provided in Contec's 2026-09-10 security notice as described in the PDF link.
Configure the device to enforce authentication on all REST API endpoints, addressing the Missing Authentication flaw (CWE-306).
Restrict network access to the device’s REST API by using firewalls, VPNs or IP whitelists, ensuring only trusted systems can contact it.
If the API is not needed, disable or block the vulnerable endpoints to eliminate exposure.

Generated by OpenCVE AI on September 15, 2026 at 15:41 UTC.

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.341% probability within 30 days)

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
https://jvn.jp/en/vu/JVNVU96551518/
https://www.contec.com/api/downloadlogger?download=/-/media/Contec/support/security-info/2026/contec_security_cps_26091000_en.pdf

History

Sep 17, 2026 8:30 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Contec Contec remote I/o Coupler Unit (server Type) Cpsn-mcb271-*
Vendors & Products		Contec Contec remote I/o Coupler Unit (server Type) Cpsn-mcb271-*

Sep 15, 2026 4:00 PM Title updated View changes

Type	Values Removed	Values Added
Title	Missing Authentication in REST API Enables Remote Read/Control of I/O Coupler

Sep 14, 2026 10:30 PM Title updated View changes

Type	Values Removed	Values Added
Title		Missing Authentication in REST API Enables Remote Read/Control of I/O Coupler

Sep 14, 2026 12:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Sep 14, 2026 7:00 AM Description updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		Missing authentication for critical function vulnerability exists in Remote I/O Coupler Unit (Server Type) CPSN-MCB271-*. An attacker may execute a REST API without authentication, which could allow the attacker to retrieve I/O values and/or control the output.
Weaknesses		CWE-306
References		https://jvn.jp/en/vu/JVNVU96551518/ https://www.contec.com/api/downloadlogger?download=/-/media/Contec/support/security-info/2026/contec_security_cps_26091000_en.pdf
Metrics		cvssV3_1 `{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}` cvssV4_0 `{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}`