Security readout for executives and security teams
Plain-English summary
CVE-2018-21189 is a post-authentication stack buffer overflow in several NETGEAR routers and gateways. An attacker needs authenticated access, but successful exploitation could severely affect confidentiality, integrity, and availability. The main business concern is older firmware still running on listed devices.
Executive priority
Treat this as a moderate-priority infrastructure hygiene issue. Prioritize internet-adjacent offices, shared networks, and devices with broad administrative access, but do not classify it as an active-exploitation emergency from the provided evidence.
Technical view
The CVE describes a stack-based buffer overflow reachable by an authenticated user on specific NETGEAR models before named firmware versions. CVSS 3.0 is 6.8 with low complexity, adjacent network access, high privileges required, no user interaction, and high CIA impact.
Likely exposure
Exposure is limited to organizations using the listed NETGEAR models on firmware older than the fixed versions, especially where administrative access is available from local or adjacent networks.
Exploitation context
The source bundle does not show CISA KEV listing or cited active exploitation. The vulnerability requires authenticated high-privilege access, which lowers likelihood but does not reduce potential device impact.
Researcher notes
Evidence is sparse: the CVE identifies affected models and fixed-version thresholds, but provides no CWE detail, exploit narrative, or vulnerable endpoint. Avoid assuming exploit availability or unauthenticated reachability without additional vendor or lab evidence.
Mitigation direction
- Inventory the listed NETGEAR models across offices and remote sites.
- Upgrade affected devices to the fixed firmware versions or later.
- Check NETGEAR guidance for model-specific firmware and support status.
- Restrict router administration to trusted administrators and trusted networks.
- Replace unsupported devices if fixed firmware is unavailable.
Validation and detection
- Confirm device model and current firmware version for each NETGEAR device.
- Compare firmware against the CVE's affected-before version list.
- Verify administrative access is limited to authorized users.
- Review administrative accounts for unexpected or stale access.
- Document remediation status for each affected model.
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-2018-21189 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/000055168/Security-Advisory-for-Post-Authentication-Stack-Overflow-on-Some-Routers-and-Gateways-PSV-2017-2606CVE 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.