Security readout for executives and security teams
Plain-English summary
This CVE affects multiple older NETGEAR routers and gateways. An unauthenticated attacker with adjacent network access could trigger a buffer overflow before login. The worst-case impact is full compromise of confidentiality, integrity, and availability on affected devices.
Executive priority
Treat this as a high-priority network device remediation item, especially for remote offices and unmanaged sites. It is not KEV-listed in the provided bundle, but pre-authentication impact on routers can create serious business risk.
Technical view
CVE-2018-21211 is a pre-authentication buffer overflow in listed NETGEAR D-series, R-series, WNDR, and WNR models before specified firmware versions. CVSS 3.0 is 8.8, with low complexity, no privileges, no user interaction, adjacent attack vector, and high C/I/A impact.
Likely exposure
Exposure is likely in small office, branch, lab, and home-office networks still running affected NETGEAR firmware. The CVSS vector indicates adjacent-network reach is required; the supplied sources do not support internet-wide exposure claims.
Exploitation context
The provided bundle does not show CISA KEV listing or active exploitation evidence. Risk remains material because the flaw is pre-authentication, low complexity, and affects network-edge devices that are often unmanaged or slow to update.
Researcher notes
The source bundle names affected firmware thresholds but does not include CWE details, exploit status, or protocol-level trigger information. Avoid assuming public exploitability beyond the adjacent-network CVSS vector and unauthenticated pre-authentication characterization.
Mitigation direction
- Inventory listed NETGEAR models and firmware versions.
- Update affected devices to the named non-affected firmware version or later.
- Follow NETGEAR advisory guidance for each exact model.
- Limit management and untrusted adjacent-network access until updated.
- Replace devices that cannot receive supported firmware.
Validation and detection
- Compare device model and firmware against the affected version list.
- Confirm upgraded firmware is at or above the fixed version threshold.
- Review network inventories for unmanaged NETGEAR routers or gateways.
- Check change records for firmware updates on affected models.
- Monitor vendor advisory updates for revised guidance.
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-2018-21211 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
- High
- CVSS
- 8.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AC:L/AV:A/A:H/C:H/I:H/PR:N/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:H/I:H/PR:N/S:U/UI:N2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
8.8HighVector: CVSS:3.0/AC:L/AV:A/A:H/C:H/I:H/PR:N/S:U/UI:N
Source materials
- CVE List V5 sourceCVE List V5
- https://kb.netgear.com/000055138/Security-Advisory-for-Pre-Authentication-Buffer-Overflow-on-Some-Routers-and-Gateways-PSV-2017-2491CVE 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.