CVE-2026-47099
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 · uneditedTeleJSON prior to 6.0.0 contains a DOM-based cross-site scripting vulnerability in the parse() function that allows attackers to execute arbitrary JavaScript by delivering a crafted JSON payload containing a malicious _constructor-name_ property value. The custom reviver passes the constructor name directly to new Function() without sanitization when recreating object prototypes, enabling attackers to inject arbitrary JavaScript through vectors such as postMessage in cross-frame communication contexts to achieve script execution within the application.
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 confidenceTeleJSON before 6.0.0 has a DOM-based XSS in its parse() function where the custom reviver accepts a _constructor-name_ property from JSON input and passes it unsanitized to new Function(), allowing arbitrary JavaScript execution when exploited via postMessage in cross-frame scenarios.
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
- 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 TeleJSON installation and versionRun 'npm list telejson' or check package.json dependencies to find the installed version of telejsonAffected if The installed version is prior to 6.0.0 (e.g., 5.x.x, 4.x.x, etc.)
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Locate parse() calls with reviver functionsSearch codebase for telejson.parse( or JSON.parse( patterns that use telejson, looking for a second argument (reviver parameter)Affected if Code uses telejson.parse() with a reviver function passed as the second argument
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Check for _constructor-name_ in JSON dataSearch application logs, network traffic, or message handlers for JSON payloads containing a '_constructor-name_' propertyAffected if The application receives or processes JSON with a '_constructor-name_' property that could reach the reviver
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Identify cross-frame communication endpointsSearch for postMessage listeners, message event handlers, or iframe/window communication code that could receive external JSON inputAffected if The application uses postMessage, iframe communication, or other cross-frame APIs that could deliver crafted JSON payloads to parse()
You are affected if TeleJSON version is below 6.0.0 AND your code uses parse() with a reviver AND accepts JSON input from cross-frame sources containing the _constructor-name_ property.
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.
dbcve · scopedUpgrade to TeleJSON 6.0.0 or later, which includes proper sanitization of the constructor name before use in new Function(). If upgrading is not possible, implement input validation to only allow predefined safe constructor names.
6.0.0
- Identify the current version of TeleJSON in your project by checking package.json or running 'npm list telejson'
- Update the TeleJSON dependency in package.json to version 6.0.0 or later (e.g., '"telejson": "^6.0.0"')
- Run 'npm install' or 'yarn install' to install the updated version
- Verify the installed version is 6.0.0 or later by running 'npm list telejson'
- Test your application to ensure the update does not break existing functionality
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing5.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-47099 — 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-2026-47099 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
- No spam, self-promotion, credentials, or personal data