CVE-2018-21155
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 stored XSS. This affects D7800 before 1.0.1.34, DM200 before 1.0.0.52, R6100 before 1.0.1.22, R7500 before 1.0.0.122, R7500v2 before 1.0.3.26, R7800 before 1.0.2.42, R8900 before 1.0.4.2, R9000 before 1.0.3.16, WNDR4300 before 1.0.2.98, WNDR4300v2 before 1.0.0.54, WNDR4500v3 before 1.0.0.54, and WNR2000v5 before 1.0.0.64.
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 · moderate confidenceStored cross-site scripting (XSS) vulnerability in NETGEAR router web management interfaces allows authenticated or potentially unauthenticated attackers to inject malicious JavaScript that executes when administrators view compromised pages. The vulnerability affects the management UI of multiple router models including D7800, R6100, R7500, R7800, R8900, R9000, WNDR4300, and WNR2000v5.
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< 1.0.1.34< 1.0.0.52< 1.0.1.22< 1.0.0.122< 1.0.3.26< 1.0.2.42< 1.0.4.2< 1.0.3.16< 1.0.2.98< 1.0.0.54CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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 the NETGEAR router modelAccess the router's web management interface and locate the model number typically displayed on the login page, in the status/dashboard section, or on a physical label on the device. Common locations in the UI are under 'Router Info', 'Device Information', or the 'Advanced' > 'Administration' > 'Router Status' page.Affected if The model matches one of: D7800, Dm200, R6100, R7500, R7800, R8900, R9000, or WNDR4300 (or WNR2000v5 mentioned in summary)
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Determine the installed firmware versionIn the router web interface, navigate to the firmware version display. This is usually found on the main status page, under 'Router Status', 'Device Information', or 'Advanced' > 'Administration' > 'Router Status'. The firmware version is displayed as a numeric string such as '1.0.2.42'.Affected if Unable to retrieve the firmware version from the web interface indicates a potential access limitation.
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Compare firmware version against affected rangesMatch your installed firmware version to the vulnerable version thresholds: D7800 < 1.0.1.34, Dm200 < 1.0.0.52, R6100 < 1.0.1.22, R7500 < 1.0.0.122 (or < 1.0.3.26 for v2), R7800 < 1.0.2.42, R8900 < 1.0.4.2, R9000 < 1.0.3.16, WNDR4300 < 1.0.2.98 (or < 1.0.0.54 for v2).Affected if Your installed version is lower than the specified threshold for your model, indicating the device is running a vulnerable firmware version.
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Verify web management interface accessibilityConfirm the router's web management interface is accessible. This can be done by accessing the router's IP address (commonly 192.168.1.1) in a web browser. Check if the login page loads successfully.Affected if The web management interface is accessible (especially remotely over WAN), increasing the potential attack surface for this XSS vulnerability.
You are affected if your NETGEAR router model is one of the listed models AND your installed firmware version is below the specified fixed version threshold for that model, particularly if the web management interface is accessible.
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 data1.0.0.521.0.0.541.0.0.122
Apply vendor-supplied firmware updates to all affected router models to the versions specified (D7800: 1.0.1.34, DM200: 1.0.0.52, R6100: 1.0.1.22, R7500: 1.0.0.122, R7500v2: 1.0.3.26, R7800: 1.0.2.42, R8900: 1.0.4.2, R9000: 1.0.3.16, WNDR4300: 1.0.2.98, WNDR4300v2: 1.0.0.54, WNDR4500v3: 1.0.0.54, WNR2000v5: 1.0.0.64). If patching is not possible, disable remote web management and restrict administrative access to trusted networks.
- Consultation2.0 h
- Implementation3.0 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-2018-21155 — 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-2018-21155 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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- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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