Node.jsApplication
CVE-2020-8252
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 implementation of realpath in libuv < 10.22.1, < 12.18.4, and < 14.9.0 used within Node.js incorrectly determined the buffer size which can result in a buffer overflow if the resolved path is longer than 256 bytes.
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 confidenceA buffer overflow vulnerability exists in libuv's realpath implementation where the buffer size is incorrectly calculated. When the resolved path exceeds 256 bytes, the function writes beyond the allocated buffer boundary, potentially allowing memory corruption or arbitrary code execution.
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
>= 10.0.0, < 10.22.1>= 12.0.0, < 12.18.4>= 14.0.0, < 14.9.0
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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/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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Check installed Node.js versionRun `node --version` or `node -p process.version` to get the exact version stringAffected if Version is 10.0.0 to <10.22.1, 12.0.0 to <12.18.4, or 14.0.0 to <14.9.0
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Check libuv library versionRun `node -p process.release.libuv` or examine the libuv binary linked to Node.js via `ldd $(which node)` and check the library file versionAffected if libuv version is below the fixed releases (typically bundled within the affected Node.js versions)
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Verify OS distribution and versionCheck if running Fedora 33 or openSUSE Leap 15.2 using `cat /etc/os-release`Affected if Running Fedora 33 or openSUSE Leap 15.2 with affected Node.js/libuv packages installed
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Identify realpath usage in applicationsReview application code for calls to `fs.realpath()`, `fs.realpathSync()`, or path.resolve() that could resolve paths exceeding 256 bytesAffected if Application uses realpath functionality with paths that could exceed 256 bytes in length
You are affected if Node.js version falls within the vulnerable ranges (10.x <10.22.1, 12.x <12.18.4, or 14.x <14.9.0) or if libuv bundled with your Node.js is from an affected version, and your application uses realpath on paths exceeding 256 bytes.
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 data10.22.112.18.414.9.0
Upgrade libuv to version 10.22.1, 12.18.4, or 14.9.0 or higher to patch the buffer size calculation flaw in the realpath function.
Fix this in Node.js
Scoped from the published advisory
- Consultation4.0 h
- Implementation4.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,504.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-8252 — 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-2020-8252 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
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