Security readout for executives and security teams
Plain-English summary
CVE-2018-21221 is a high-severity pre-authentication buffer overflow in some NETGEAR routers and gateways. An attacker does not need credentials. The documented affected models are D3600, D6000, and R9000 running firmware older than the fixed versions.
Executive priority
Treat this as a priority remediation item for any matching NETGEAR devices. The business concern is potential compromise or outage of routing equipment without credential theft, although active exploitation is not evidenced in the supplied sources.
Technical view
The CVE describes an unauthenticated buffer overflow affecting NETGEAR D3600 before 1.0.0.67, D6000 before 1.0.0.67, and R9000 before 1.0.2.52. CVSS 3.0 is 8.8 with adjacent-network attack vector, no privileges, no user interaction, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely where the named NETGEAR models remain deployed with outdated firmware and reachable from an attacker on an adjacent network. The provided record does not identify other products or broader firmware families.
Exploitation context
The supplied sources do not show CISA KEV listing or active exploitation. The risk remains serious because the flaw is unauthenticated, low complexity, and affects network edge equipment.
Researcher notes
The public record gives model and version bounds but limited technical detail. Avoid assuming the vulnerable interface, protocol, or exploit path beyond pre-authentication buffer overflow and adjacent-network reachability indicated by CVSS.
Mitigation direction
- Upgrade D3600 and D6000 firmware to 1.0.0.67 or later.
- Upgrade R9000 firmware to 1.0.2.52 or later.
- Review the NETGEAR advisory for model-specific firmware guidance.
- Replace or isolate devices that cannot be confirmed patched.
- Limit device management exposure to trusted networks while remediation is pending.
Validation and detection
- Inventory NETGEAR D3600, D6000, and R9000 devices in all sites.
- Record installed firmware versions for each identified device.
- Compare versions against the fixed thresholds in the CVE record.
- Confirm remediation through device administration or asset management evidence.
- Document any unsupported or unreachable devices as residual risk.
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-2018-21221 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/000055116/Security-Advisory-for-Pre-Authentication-Buffer-Overflow-on-Some-Routers-and-Gateways-PSV-2017-2459CVE 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.