Security readout for executives and security teams
Plain-English summary
CVE-2018-21166 is a denial-of-service issue in several older NETGEAR router models. A successful attack could disrupt router availability, but the CVSS data indicates no confidentiality or integrity impact. The attack is rated medium severity and appears limited to adjacent-network access with high privileges.
Executive priority
Prioritize remediation for business-critical sites where these routers support office connectivity, remote access, or segmented networks. The main business risk is service disruption rather than data theft.
Technical view
The CVSS 3.0 vector is AV:A/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H, indicating an adjacent attacker with high privileges can trigger high availability impact. Affected firmware is listed for R6100, R7500, R7800, R8900, R9000, WNDR3700v4, WNDR4300 variants, WNDR4500v3, and WNR2000v5 before specified versions.
Likely exposure
Exposure is most relevant where affected NETGEAR routers remain deployed with vulnerable firmware and reachable from local or adjacent networks. Internet-scale exposure is not supported by the provided CVSS vector or sources.
Exploitation context
The source bundle does not show CISA KEV listing or cited evidence of active exploitation. Treat this as a known availability weakness requiring firmware hygiene, not as a confirmed active campaign.
Researcher notes
The public data is sparse and does not include CWE details or exploit mechanics. Analysis should stay anchored to model and firmware matching, CVSS constraints, and the NETGEAR advisory rather than assuming broader product impact.
Mitigation direction
- Identify whether any listed NETGEAR router models are deployed.
- Upgrade affected devices to the listed fixed firmware version or later.
- Review the NETGEAR advisory for device-specific firmware guidance.
- Restrict administrative access to trusted local management networks.
- Replace unsupported devices if current fixed firmware is unavailable.
Validation and detection
- Inventory router model and firmware version for each NETGEAR device.
- Compare installed firmware against the affected version thresholds.
- Confirm management access is limited to trusted administrators.
- Review logs or monitoring for unexplained router restarts or outages.
- Document remediation status for each affected router.
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.
CVE-2018-21166 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
- 4.5 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AC:L/AV:A/A:H/C:N/I:N/PR:H/S:U/UI: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:3.0/AC:L/AV:A/A:H/C:N/I:N/PR:H/S:U/UI:N0.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
4.5MediumVector: CVSS:3.0/AC:L/AV:A/A:H/C:N/I:N/PR:H/S:U/UI:N
Source materials
- CVE List V5 sourceCVE List V5
- https://kb.netgear.com/000055193/Security-Advisory-for-Denial-of-Service-on-Some-Routers-PSV-2017-3167CVE reference · x_refsource_CONFIRM
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.