Security readout for executives and security teams
Plain-English summary
CVE-2021-38523 affects NETGEAR R6400 routers running firmware before 1.0.1.70. An authenticated user could trigger a stack-based buffer overflow. The public record rates it medium, but availability impact is high, so unmanaged or shared-admin routers should be prioritized.
Executive priority
Treat this as a moderate-priority network device hygiene issue. It is not documented as actively exploited in the supplied sources, but affected routers can suffer high availability impact and should be updated during the next maintenance window.
Technical view
The CVE describes a post-authentication stack-based buffer overflow in NETGEAR R6400 firmware before 1.0.1.70. CVSS 3.1 is 6.9 with adjacent attack vector, high privileges required, changed scope, low integrity impact, and high availability impact.
Likely exposure
Exposure is limited to NETGEAR R6400 devices on firmware earlier than 1.0.1.70. Risk is highest where authenticated router access is broadly shared or reachable from adjacent network segments.
Exploitation context
The provided sources do not show CISA KEV listing or confirmed active exploitation. The flaw requires authentication, and the CVSS vector indicates adjacent network access and high privileges are required.
Researcher notes
Public metadata is sparse: no CWE is listed and affected CPE data is unavailable in the bundle. Analysis should stay tied to NETGEAR R6400 firmware before 1.0.1.70 and the authenticated, adjacent-network CVSS conditions.
Mitigation direction
- Upgrade NETGEAR R6400 firmware to version 1.0.1.70 or later.
- Review the NETGEAR advisory for any model-specific guidance.
- Restrict router administration access to trusted administrators only.
- Limit management exposure to trusted local or management networks.
- Rotate router credentials where shared access may exist.
Validation and detection
- Inventory NETGEAR R6400 devices and record firmware versions.
- Confirm no affected device runs firmware earlier than 1.0.1.70.
- Review router management access lists and administrator accounts.
- Check logs for unexpected authenticated configuration activity.
- Track the NETGEAR advisory for updated remediation details.
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
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CVE-2021-38523 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AC:L/AV:A/A:H/C:N/I:L/PR:H/S:C/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:3.1/AC:L/AV:A/A:H/C:N/I:L/PR:H/S:C/UI:N1.74.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.9MediumVector: CVSS:3.1/AC:L/AV:A/A:H/C:N/I:L/PR:H/S:C/UI:N
Source materials
- CVE List V5 sourceCVE List V5
- https://kb.netgear.com/000063771/Security-Advisory-for-Post-Authentication-Stack-Overflow-on-R6400-PSV-2019-0166CVE reference · x_refsource_MISC
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.