Security readout for executives and security teams
Plain-English summary
CVE-2026-4309 affects multiple NEC Aterm router and extender models. A missing authorization flaw may let a network attacker view specific device information and change settings without proper permission. Business urgency is moderate: exposure depends on whether affected devices are reachable from untrusted networks, but unauthorized configuration changes can disrupt connectivity or weaken security.
Executive priority
Prioritize within normal vulnerability remediation cycles, faster for devices exposed to untrusted networks or supporting critical connectivity. Treat unsupported affected devices as replacement candidates if NEC provides no fix.
Technical view
The issue is CWE-862 Missing Authorization in NEC Platforms Aterm Series. CVSS v4.0 is 6.3, with network attack vector, no privileges or user interaction, high attack complexity, and low confidentiality, integrity, and availability impact. Some models list fixed firmware thresholds; others are marked affected for all versions in the provided record.
Likely exposure
Organizations using listed NEC Aterm models are potentially exposed, especially where management interfaces are reachable from LAN guests, shared networks, or the internet. The source does not confirm internet-wide exposure, default configuration impact, or affected services.
Exploitation context
No CISA KEV listing is indicated, and the provided sources do not report active exploitation or public exploit availability. The CVSS vector indicates remote network reachability but high attack complexity.
Researcher notes
Evidence is limited to the CVE record and NEC advisory. The advisory identifies missing authorization enabling information access and settings changes via network, but does not provide endpoint-level details, exploit prerequisites beyond CVSS, or evidence of exploitation.
Mitigation direction
- Identify all NEC Aterm models listed in the advisory and CVE record.
- Update models with named fixed versions to the vendor-listed firmware or later.
- For models listed as all versions, check NEC guidance for support status and remediation.
- Restrict management access to trusted administrative networks only.
- Disable unnecessary remote administration where supported by vendor configuration.
- Replace or isolate unsupported affected devices if no vendor remediation is available.
Validation and detection
- Inventory NEC Aterm devices by exact model and firmware version.
- Compare firmware versions against the affected-version list in NEC’s advisory.
- Confirm administrative interfaces are not exposed to untrusted networks.
- Review device settings for unauthorized changes after remediation.
- Monitor NEC’s advisory page for updates on all-version affected models.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-862: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-4309 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.3 (4.0)
- Known Exploited
- No
- Published
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
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
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——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
6.3MediumVector: 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
Source materials
- CVE List V5 sourceCVE List V5
- https://jpn.nec.com/security-info/secinfo/nv26-001_en.htmlCVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Missing Authorization
Missing Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.