Severity by source
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
No authentication required on REST API (PR:N, AC:L); impact is limited I/O read and output write on the device (C:L/I:L); no availability impact or scope change described.
Primary rating from Vendor (jpcert).
CVSS VectorVendor: jpcert
Lifecycle Timeline
3DescriptionCVE.org
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.
AnalysisAI
Unauthenticated REST API access on Contec's CPSN-MCB271 series Remote I/O Coupler Unit (Server Type) allows any network-reachable attacker to read industrial I/O sensor values and issue output control commands without credentials. The vulnerability arises from a complete absence of authentication on the device's REST interface, exposing physical process control functions directly over the network. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The CPSN-MCB271 device must be network-reachable and its REST API port must be accessible from the attacker's network position. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L) correctly captures the trivial exploitation path - no authentication, no complexity, no user interaction required - but the low impact ratings (VC:L/VI:L) may understate real-world consequence in OT environments where physical output control is the device's core function. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Consult the Contec security advisory (https://www.contec.com/api/downloadlogger?download=/-/media/Contec/support/security-info/2026/contec_security_cps_26091000_en.pdf) and JVN advisory JVNVU96551518 (https://jvn.jp/en/vu/JVNVU96551518/) for official patch or firmware update guidance - exact patched firmware version numbers are not confirmed from currently available data. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Credential disclosure in Contec's Remote I/O Coupler Unit (Server Type) CPSN-MCB271 enables an attacker who obtains a de
Stack-based buffer overflow in Contec Remote I/O Coupler Unit (Server Type) CPSN-MCB271-* allows an authenticated remote
Out-of-bounds write in CONPROSYS nano Series Remote I/O Coupler Units from Contec Co., Ltd. enables remote attackers wit
Cross-site scripting in CONTEC's CONPROSYS nano Series industrial remote I/O coupler units allows an unauthenticated att
Cross-site request forgery affects a broad range of Contec industrial data loggers, flow computers, and remote I/O coupl
Plaintext credential storage in CONTEC's CONPROSYS nano Series industrial remote I/O devices exposes passwords to attack
Same technique Authentication Bypass
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-77237
GHSA-5w7g-j8f5-2795