EUVD-2026-77239
GHSA-622w-5wv2-xm5f
Severity by source
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/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
Backup file access is the attack prerequisite (AC:H); vendor assesses no authentication required to obtain backup (PR:N); impact is purely credential confidentiality with no integrity or availability effect.
Primary rating from Vendor (jpcert).
CVSS VectorVendor: jpcert
Lifecycle Timeline
6DescriptionCVE.org
Insufficiently protected credentials issue exists in Remote I/O Coupler Unit (Server Type) CPSN-MCB271-*. If this vulnerability is exploited, sensitive information may be restored from a backup file.
AnalysisAI
Credential disclosure in Contec's Remote I/O Coupler Unit (Server Type) CPSN-MCB271 enables an attacker who obtains a device backup file to recover sensitive credentials stored within it in an insufficiently protected form. The root cause (CWE-522) means credentials are not rendered unrecoverable within backup archives, so any party who accesses a backup file can extract usable authentication material. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that an attacker obtain a backup file generated by the CPSN-MCB271 device. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 score of 8.2 reflects high confidentiality impact (VC:H) with no integrity or availability consequence, and the AC:H metric captures a genuine prerequisite: the attacker must first obtain a backup file before any credential recovery is possible. … 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 | Apply the firmware update or configuration change detailed in Contec's official security advisory, accessible via the Contec support portal (contec_security_cps_26091000_en.pdf linked through https://www.contec.com/api/downloadlogger?download=/-/media/Contec/support/security-info/2026/contec_security_cps_26091000_en.pdf), and review the JPCERT/CC coordination notice at https://jvn.jp/en/vu/JVNVU96551518/ for supplemental guidance. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Inventory all deployed CPSN-MCB271 devices and locate all backup files currently stored across your infrastructure; audit and document current access controls for backup storage locations. …
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Unauthenticated REST API access on Contec's CPSN-MCB271 series Remote I/O Coupler Unit (Server Type) allows any network-
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 weakness CWE-522 – Insufficiently Protected Credentials
View allSame technique Information Disclosure
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External POC / Exploit Code
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