Which versions of Aterm W1200Ex Ms are affected by CVE-2026-4309?

CVE-2026-4309 presents moderate security risk, a missing authorization vulnerability rated CVSS 6.3. Attackers could gain access beyond their authorized level.

How to fix or mitigate CVE-2026-4309?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.

Aterm W1200Ex Ms CVE-2026-4309

Q: What is the CVSS score of CVE-2026-4309?

CVE-2026-4309 has a CVSS 4.0 base score of 6.3 (Medium). CVSS vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/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. EPSS exploitation probability: 0.0%.

EUVD-2026-16583 MEDIUM

Missing Authorization (CWE-862)

2026-03-27 NEC

GHSA-gqp3-283g-mgqc

Authentication Bypass Aterm W1200Ex Ms Aterm Wg1200Hp2 Aterm Wg1900Hp Aterm Wg1200Hs2 Aterm Wg1800Hp3 Aterm Wg1200Hp3 Aterm Wg1900Hp2 Aterm Wg1200Hs3 Aterm Wg1800Hp4 Aterm Wg1200Hp4 Aterm Wg1200Hs4 Aterm Wx1500Hp Aterm Wg2600Hs Aterm Wf1200Cr Aterm Wg1200Cr Aterm Wg2600Hp4 Aterm Wg2600Hm4 Aterm Wg2600Hs2 Aterm Wx3000Hp Aterm Wx3600Hp

6.3

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

6.3 MEDIUM

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/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

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

EUVD ID Assigned

Mar 27, 2026 - 12:00 euvd

EUVD-2026-16583

Analysis Generated

Mar 27, 2026 - 12:00 vuln.today

CVE Published

Mar 27, 2026 - 11:46 nvd

MEDIUM 6.3

DescriptionCVE.org

Missing Authorization vulnerability in NEC Platforms, Ltd. Aterm Series allows a attacker to get a specific device information and change the settings via network.

AnalysisAI

NEC Aterm wireless router series (W1200Ex-MS, WG1200HP2, WG1900HP, WG1800HP3, WG1800HP4, WG1200HP3, WG1200HP4, WG1200HS2, WG1200HS3, WX1500HP, WX3000HP, WX3600HP, WG2600HS, WG2600HS2, WG2600HP4, WG2600HM4, WF1200CR, WG1200CR, and others) suffer from missing authorization controls that enable remote attackers to enumerate device configuration details and modify settings without proper access controls. The vulnerability stems from CWE-862 (Missing Authorization) in the device management interface, allowing unauthenticated or inadequately authenticated network-accessible requests to interact with sensitive administrative functions. No CVSS score, EPSS probability estimate, or public exploit code has been disclosed, and CISA KEV status is unknown.

Technical ContextAI

NEC Aterm Series routers are consumer and small-business wireless networking devices that expose web-based device management interfaces for configuration and monitoring. The vulnerability resides in the authorization layer of this management interface, which fails to properly validate user privileges before permitting access to sensitive operations. CWE-862 (Missing Authorization) classifies this as a broken access control flaw where the application does not perform authorization checks after authentication or skips authentication entirely for certain endpoints. The affected CPE strings (cpe:2.3:a:nec_platforms,_ltd.:aterm_*) cover multiple product lines and firmware revisions, suggesting the flaw is systemic across the Aterm platform. Remote attackers can exploit this via standard HTTP/HTTPS requests to the router's management interface without requiring valid credentials or with minimal privilege escalation.

RemediationAI

Contact NEC Platforms, Ltd. and check https://jpn.nec.com/security-info/secinfo/nv26-001_en.html for firmware patches addressing CVE-2026-4309. If a patched firmware version is available, update your Aterm device immediately through the device management interface or via USB recovery. Until patching is complete, implement network mitigations: (1) restrict access to the router's management interface to trusted administrative hosts only via firewall rules; (2) change the default management port or disable remote management if the feature is enabled; (3) isolate router management traffic on a separate administrative VLAN; (4) use strong administrative credentials and rotate passwords immediately if unauthorized access is suspected. For organizations managing multiple Aterm devices, establish a firmware update schedule and centralized monitoring to detect unauthorized configuration changes.