CVE-2014-6393
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 · uneditedThe Express web framework before 3.11 and 4.x before 4.5 for Node.js does not provide a charset field in HTTP Content-Type headers in 400 level responses, which might allow remote attackers to conduct cross-site scripting (XSS) attacks via characters in a non-standard encoding.
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 confidenceExpress.js before version 3.11 and 4.x before 4.5 omits the charset parameter in HTTP Content-Type headers for 400-level error responses. Without an explicit charset, browsers may interpret response content using non-standard encodings, potentially allowing attackers to inject XSS payloads through specially crafted character sequences that bypass sanitization when rendered.
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<= 3.10.5= 4.0.0= 4.1.0= 4.1.1= 4.1.2= 4.2.0= 4.3.0= 4.3.1= 4.3.2= 4.4.0= 4.4.1= 4.4.2CVSS 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:3.0/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 Express.js dependencyCheck your package.json or node_modules for express dependency. Run `npm list express` or inspect the express version file at node_modules/express/package.jsonAffected if Express is not present in the project dependencies
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Determine installed Express versionRun `npm list express` or read the version from node_modules/express/package.jsonAffected if The version is 3.10.5 or lower, or one of 4.0.0, 4.1.0, 4.1.1, 4.1.2, 4.2.0, 4.3.0, 4.3.1, 4.3.2, 4.4.0, 4.4.1, or 4.4.2
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Verify application handles error responsesSearch your application code for error handlers (app.error(), process.on('uncaughtException'), or routes that return 400-level status codes) and examine how Content-Type headers are setAffected if Your application returns 400-level HTTP error responses without explicitly setting charset in the Content-Type header
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Inspect HTTP response headers for error pagesTrigger a 400-level error in your running application (e.g., send a malformed request) and capture the response headers using curl -I or browser dev tools. Examine the Content-Type header for the presence of charset parameterAffected if The Content-Type header for error responses lacks a charset parameter (e.g., shows 'text/html' instead of 'text/html; charset=utf-8')
You are affected if your installed Express.js version matches one of the vulnerable versions listed AND your application returns 400-level error responses without an explicit charset in the Content-Type header.
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 dataUpgrade Express.js to version 3.11 or later, or 4.5 or later. As a workaround, manually ensure all error response Content-Type headers include an explicit charset (e.g., 'text/html; charset=utf-8').
- Consultation2.0 h
- Implementation2.0 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-2014-6393 — 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-2014-6393 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
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