Security readout for executives and security teams
Plain-English summary
This vulnerability affects several older NETGEAR gateways and routers. A logged-in, high-privilege user on an adjacent network could trigger a stack overflow with severe device impact. It is not marked as known exploited in the supplied KEV signal, but exposed or poorly governed admin access raises business risk.
Executive priority
Treat this as a moderate-priority network hygiene and legacy device issue. The strongest urgency is for environments still running old NETGEAR firmware or allowing broad administrative access. Prioritize firmware verification, management-plane restriction, and replacement planning for devices that cannot be updated.
Technical view
CVE-2018-21148 is a post-authentication stack-based buffer overflow in listed NETGEAR devices before specified firmware versions. CVSS 3.0 is 6.8 with adjacent-network access, low attack complexity, high privileges required, no user interaction, unchanged scope, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely where affected NETGEAR models remain in service with firmware below the fixed versions, especially on networks where router administration is reachable by untrusted or weakly governed users. The CVE description names D7800, DM200, R6100, R7500, R7800, R8900, R9000, WNDR, and WNR2000v5 variants.
Exploitation context
The supplied sources do not show active exploitation, and the KEV flag is false. Exploitation requires authenticated, high-privilege access and adjacent-network reachability, reducing broad internet-scale risk but leaving meaningful risk from compromised admin accounts, insiders, shared credentials, or exposed management interfaces.
Researcher notes
The source data identifies affected model/version thresholds but does not provide CWE mapping, exploit details, or confirmed exploitation. The key technical constraints are adjacent-network access and high privileges. Validation should focus on firmware inventory, management-plane reachability, and whether administrative credentials could be misused.
Mitigation direction
- Inventory NETGEAR models named in the advisory and CVE description.
- Upgrade affected devices to the fixed firmware version or later listed for each model.
- Restrict administrative access to trusted management networks only.
- Rotate router administrator credentials where exposure or credential sharing is suspected.
- Check NETGEAR guidance for any model-specific replacement or support limitations.
Validation and detection
- Compare each device model and firmware version against the CVE fixed-version list.
- Verify router administration is not reachable from untrusted network segments.
- Confirm administrative accounts are limited to authorized personnel only.
- Review logs for unexpected administrator access where logging is available.
- Document unsupported or unpatchable devices for replacement planning.
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-2018-21148 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
- 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
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:H/S:U/UI:N0.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
6.8MediumVector: CVSS:3.0/AC:L/AV:A/A:H/C:H/I:H/PR:H/S:U/UI:N
Source materials
- CVE List V5 sourceCVE List V5
- https://kb.netgear.com/000059485/Security-Advisory-for-Post-Authentication-Stack-Overflow-on-Some-Gateways-and-Routers-PSV-2017-3157CVE 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.