Node.jsApplication
CVE-2020-8201
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 · uneditedNode.js < 12.18.4 and < 14.11 can be exploited to perform HTTP desync attacks and deliver malicious payloads to unsuspecting users. The payloads can be crafted by an attacker to hijack user sessions, poison cookies, perform clickjacking, and a multitude of other attacks depending on the architecture of the underlying system. The attack was possible due to a bug in processing of carrier-return symbols in the HTTP header names.
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 confidenceNode.js versions prior to 12.18.4 and 14.11 contain a bug in HTTP header parsing where carriage-return symbols (\r) in header names are improperly processed, enabling HTTP desync (request smuggling) attacks. Attackers can craft malicious requests that bypass front-end proxies or load balancers to smuggle payloads through to backend servers, allowing session hijacking, cookie poisoning, and other attacks.
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
Node.jsApplication
>= 12.0.0, < 12.18.4>= 14.0.0, < 14.11.0
FedoraOperating system
= 33= 15.2CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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 Node.js versionRun `node --version` or `node -v` to obtain the Node.js interpreter versionAffected if Version is 12.0.0 through 12.18.3, or 14.0.0 through 14.10.0 (matches < 12.18.4 or < 14.11.0)
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Check Node.js package versionIf using a package manager, run `npm list node` or check package.json dependencies for the node version specificationAffected if The pinned or resolved version falls within the affected ranges
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Identify running Node.js HTTP serversList all running processes and filter for node.js or node executables handling HTTP traffic: `ps aux | grep node` or `netstat -tlnp` to find processes listening on HTTP ports (80, 443, or custom)Affected if Node.js processes are listening on HTTP ports and the Node.js version is in the affected range
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Check for HTTP request handling codeInspect application source code for use of http.Server, express, or other HTTP frameworks that rely on Node.js built-in HTTP parsingAffected if The application uses Node.js HTTP servers and the Node.js version is vulnerable
You are affected if any installed Node.js instance runs version 12.0.0-12.18.3 or 14.0.0-14.10.0 and handles HTTP requests.
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 data12.18.414.11.0
Upgrade Node.js to version 12.18.4, 14.11, or later. For legacy systems that cannot upgrade immediately, implement request validation at proxies and ensure backend servers reject ambiguous HTTP requests with strict parsing rules.
Fix this in Node.js
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-8201 — 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-2020-8201 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data