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CVE Record

CVE-2018-21200: Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user.

Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects R7800 before 1.0.2.40 and R9000 before 1.0.3.6.

MediumCVSS 6.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This issue affects two NETGEAR router models running older firmware. A highly privileged, authenticated user on an adjacent network could trigger a stack-based buffer overflow, potentially compromising confidentiality, integrity, and availability of the device. The business concern is older router firmware with administrative access paths still reachable.

Executive priority

Treat as a targeted infrastructure hygiene issue. Prioritize remediation if these routers protect offices, remote sites, or sensitive networks, because successful exploitation could affect device control and network availability despite the high-privilege requirement.

Technical view

CVE-2018-21200 is a post-authentication stack-based buffer overflow in certain NETGEAR devices. The sources name R7800 before firmware 1.0.2.40 and R9000 before firmware 1.0.3.6. CVSS 3.0 is 6.8, with adjacent-network attack vector, high privileges required, no user interaction, and high impact ratings.

Likely exposure

Exposure is limited to organizations using NETGEAR R7800 or R9000 routers below the fixed firmware versions, especially where router administration is reachable from local or adjacent networks by privileged users.

Exploitation context

The provided sources do not show CISA KEV listing or confirmed active exploitation. The vulnerability requires authenticated, high-privilege access and adjacent-network reachability, which lowers broad internet risk but remains serious for compromised admin accounts or insider scenarios.

Researcher notes

The source bundle provides fixed versions and CVSS details but not vulnerable code paths, proof-of-concept status, or detailed exploit mechanics. CVE affected-product metadata is sparse, so validation should rely on model and firmware confirmation against NETGEAR’s advisory.

Mitigation direction

  • Update R7800 devices to firmware 1.0.2.40 or later.
  • Update R9000 devices to firmware 1.0.3.6 or later.
  • Restrict router administration to trusted management networks.
  • Review NETGEAR advisory for current vendor guidance.
  • Replace devices that cannot run supported firmware.

Validation and detection

  • Inventory NETGEAR R7800 and R9000 routers in all environments.
  • Record current firmware versions from device administration interfaces.
  • Confirm R7800 firmware is 1.0.2.40 or later.
  • Confirm R9000 firmware is 1.0.3.6 or later.
  • Verify administrative access is not broadly reachable.
  • Review admin account hygiene and recent management activity.
Prepared
Confidence
medium
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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

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CVE-2018-21200 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.8 (3.0)
Known Exploited
No
Published

Vector: CVSS:3.0/AC:L/AV:A/A:H/C:H/I:H/PR:H/S:U/UI:N

Official CVE source material

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.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
6.8CVSS 3.0MediumCVSS:3.0/AC:L/AV:A/A:H/C:H/I:H/PR:H/S:U/UI:N0.95.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

6.8Medium
CVSS 3.0 vector shape for CVE-2018-21200Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.0/AC:L/AV:A/A:H/C:H/I:H/PR:H/S:U/UI:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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