CVE-2018-21187
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedCertain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D7800 before 1.0.1.30, R7500 before 1.0.0.122, R7500v2 before 1.0.3.24, R7800 before 1.0.2.40, R9000 before 1.0.2.52, WNDR3700v4 before 1.0.2.92, WNDR4300 before 1.0.2.94, WNDR4300v2 before 1.0.0.50, WNDR4500v3 before 1.0.0.50, and WNR2000v5 before 1.0.0.62.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceMultiple NETGEAR router models contain a stack-based buffer overflow vulnerability that can be exploited by an authenticated user. The overflow occurs in the firmware's web management interface, likely in a parameter handling routine, allowing an authenticated attacker to overwrite stack memory and potentially execute arbitrary code with elevated privileges.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 1.0.1.30< 1.0.0.122< 1.0.3.24< 1.0.2.40< 1.0.2.52< 1.0.2.92< 1.0.2.94< 1.0.0.50< 1.0.0.50< 1.0.0.62CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Adjacent
- Complexity
- Low
- Privileges
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify router modelLog into the web management interface and locate the model number on the status or administration page, or check the product label on the device itselfAffected if The model matches one of the affected models: D7800, R7500, R7800, R9000, Wndr3700, Wndr4300, Wndr4500, or Wnr2000
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Check installed firmware versionIn the web management interface, navigate to the Router Status or Administration > Firmware Upgrade page to view the current firmware version numberAffected if The installed firmware version is lower than the fixed version for your model (see version ranges in CVE details)
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Verify web management interface is accessibleAttempt to access the router's web interface by entering the router's LAN IP address in a web browserAffected if The web management interface is reachable from an untrusted network (the vulnerability requires authenticated access, so this is a prerequisite condition)
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Confirm admin credentials existCheck if there are any user accounts configured with access to the router's web management interfaceAffected if At least one administrative account exists with access to the router (the vulnerability requires authentication to exploit)
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Compare version against affected rangesCross-reference your identified model and firmware version against the affected version ranges: D7800 < 1.0.1.30, R7500 < 1.0.0.122 or < 1.0.3.24, R7800 < 1.0.2.40, R9000 < 1.0.2.52, Wndr3700 < 1.0.2.92, Wndr4300 < 1.0.2.94 or < 1.0.0.50, Wndr4500 < 1.0.0.50, Wnr2000 < 1.0.0.62Affected if Your model and firmware version fall within any of the listed vulnerable version ranges
You are affected if your NETGEAR router model is one of the eight listed models AND your current firmware version is below the specified fixed version for that model AND the web management interface is accessible with valid credentials.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data1.0.0.501.0.0.621.0.0.122
Apply the vendor-supplied firmware updates for each affected model to the specified version or later. If updates are unavailable, restrict web management interface access to trusted networks or VPN connections only.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-21187 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2018-21187 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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