CVE-2023-39333
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 · uneditedMaliciously crafted export names in an imported WebAssembly module can inject JavaScript code. The injected code may be able to access data and functions that the WebAssembly module itself does not have access to, similar to as if the WebAssembly module was a JavaScript module. This vulnerability affects users of any active release line of Node.js. The vulnerable feature is only available if Node.js is started with the `--experimental-wasm-modules` command line option.
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 confidenceThis is a JavaScript code injection vulnerability in Node.js WebAssembly module handling. When Node.js is started with the experimental `--experimental-wasm-modules` flag, maliciously crafted export names in an imported WASM module can inject arbitrary JavaScript code. The injected code can access data and functions outside the WebAssembly module's intended sandbox, similar to JavaScript module behavior.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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.
-
Identify Node.js versionRun `node --version` to get the installed Node.js versionAffected if Version falls within the affected range for this CVE (compare to Node.js security advisories for CVE-2023-39333)
-
Check command-line argumentsInspect running Node.js processes using `ps aux | grep node` or review startup scripts for the presence of `--experimental-wasm-modules`Affected if The flag `--experimental-wasm-modules` appears in any Node.js launch command
-
Check NODE_OPTIONS environment variableRun `echo $NODE_OPTIONS` on Linux/Mac or `echo %NODE_OPTIONS%` on Windows to inspect environment-level Node.js flagsAffected if NODE_OPTIONS contains `--experimental-wasm-modules`
-
Review deployment configurationsExamine package.json scripts, Dockerfiles, pm2 configs, systemd service files, or any deployment scripts for the experimental wasm flagAffected if Any configuration specifies `--experimental-wasm-modules` as a startup argument
Environment is affected only if running a vulnerable Node.js version AND the `--experimental-wasm-modules` flag is enabled in command line, environment, or configuration files
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 dataAvoid using `--experimental-wasm-modules` in production environments until a patch is applied. If required, ensure all WebAssembly modules come from trusted sources and consider disabling the experimental flag until Node.js is updated to a patched version.
- Consultation4.0 h
- Implementation2.0 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 $4,928.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-39333 — 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-2023-39333 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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