ReactFramework / library · Facebook
CVE-2018-6341
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 · uneditedReact applications which rendered to HTML using the ReactDOMServer API were not escaping user-supplied attribute names at render-time. That lack of escaping could lead to a cross-site scripting vulnerability. This issue affected minor releases 16.0.x, 16.1.x, 16.2.x, 16.3.x, and 16.4.x. It was fixed in 16.0.1, 16.1.2, 16.2.1, 16.3.3, and 16.4.2.
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 confidenceReact applications using ReactDOMServer API to render HTML failed to escape user-supplied attribute names at render-time, allowing injection of malicious attribute names that could execute arbitrary JavaScript via cross-site scripting (XSS).
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
ReactFramework / library
>= 16.0.0, < 16.0.1>= 16.1.0, < 16.1.2>= 16.2.0, < 16.2.1>= 16.3.0, < 16.3.3>= 16.4.0, < 16.4.2CVSS 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 installed React versionRun `npm list react` or check package.json for the react package version numberAffected if The version falls within any of these ranges: >= 16.0.0 and < 16.0.1, or >= 16.1.0 and < 16.1.2, or >= 16.2.0 and < 16.2.1, or >= 16.3.0 and < 16.3.3, or >= 16.4.0 and < 16.4.2
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Locate ReactDOMServer usage in codebaseSearch source code files for imports or requires of 'react-dom/server' or references to methods such as renderToString, renderToStaticMarkup, renderToNodeStream, or renderToStaticNodeStreamAffected if The application imports or uses ReactDOMServer API for server-side rendering
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Inspect attribute handling in server-rendered componentsReview code paths that pass data to server rendering methods (renderToString, renderToStaticMarkup, etc.) and identify any instance where user-supplied input or dynamic data is used as an attribute name in JSX elementsAffected if User-controlled data flows into the attribute name position of JSX elements that are rendered via ReactDOMServer methods
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Verify exposure of server-rendered outputConfirm that the output from ReactDOMServer rendering methods is served to end users (e.g., via HTTP responses, API endpoints, or hydrated on the client)Affected if The server-rendered HTML is returned to browsers without additional server-side escaping of attribute names
You are affected if your React version is in the vulnerable ranges AND your application uses ReactDOMServer to render HTML from user input as attribute names that are served to clients.
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 data16.0.116.1.216.2.1
Update React to patched versions (16.0.1, 16.1.2, 16.2.1, 16.3.3, or 16.4.2 or later) and audit any code that passes user input as attribute names to server-side rendering methods.
Fix this in React
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-6341 — 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-2018-6341 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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