EUVD-2026-37119
GHSA-fxj4-v3m4-37hj
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:L/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
Network-reachable, no auth required (PR:N); scope changed because serial-attached downstream systems are impacted; no confidentiality loss, limited integrity and availability disruption.
Primary rating from Vendor (Moxa).
CVSS VectorVendor: Moxa
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:L/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
Lifecycle Timeline
1DescriptionCVE.org
A denial-of-service vulnerability exists in NPort devices because of improper access control on the command port. The command interface does not properly validate whether a sender is associated with a valid data port session before accepting break signal commands. A remote attacker with network access can send crafted requests to disrupt serial communication for an active user session.
AnalysisAI
Serial device servers in the Moxa NPort 6000 and CN2600 product lines expose a command port that accepts break signal commands without verifying the sender holds a valid associated data port session. Remote unauthenticated attackers with network access to the command port can disrupt active serial communication sessions, causing a denial of service for any device or system relying on that serial link. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | No authentication or prior session establishment is required by the attacker. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 score of 6.9 (Medium) with vector AV:N/AC:L/AT:N/PR:N/UI:N reflects a low-complexity, unauthenticated, network-accessible attack with limited impact - VC:N/VI:L/VA:L on the vulnerable system and SA:L on subsequent systems (serial-attached devices). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker on the same network segment - or reaching the NPort command port through a misconfigured firewall - crafts and sends a break signal command to the device's command port without holding an active data port session. Because the command port performs no session-association validation, the break command is accepted and applied, immediately disrupting the active serial communication session for a legitimate connected user or system. … |
| Remediation | Consult the Moxa advisory at https://www.moxa.com/en/support/product-support/security-advisory/mpsa-262370-cve-2026-10831-improper-authorization-vulnerability-in-serial-device-servers for firmware updates and exact patched version numbers, which are not specified in the currently available data. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-862 – Missing Authorization
View allSame technique Authentication Bypass
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External POC / Exploit Code
Leaving vuln.today