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React Server Dom ParcelFramework / library · Facebook

CVE-2026-23870

HIGH · 7.5 CVSS v3.1 Published 2026-05-06
Fix available
A fix is available. Upgrade to after 19.2.5 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
A denial of service vulnerability could be triggered by sending specially crafted HTTP requests to server function endpoints, this could lead to server crashes, out-of-memory exceptions or excessive CPU usage; affecting the following packages: react-server-dom-webpack, react-server-dom-parcel, react-server-dom-turbopack (versions 19.0.0 through 19.0.5, 19.1.0 through 19.1.6, and 19.2.0 through 19.2.5).

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 confidence

A denial of service vulnerability in React Server Components packages (react-server-dom-webpack, react-server-dom-parcel, react-server-dom-turbopack) where specially crafted HTTP requests to server function endpoints can trigger server crashes, out-of-memory exceptions, or excessive CPU consumption.

MitigationUpgrade affected React packages to patched versions when available, and implement rate limiting or request validation on server function endpoints as a defense-in-depth measure.

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
React Server Dom ParcelFramework / library
Affected:>= 19.0.0, <= 19.0.5>= 19.1.0, <= 19.1.6>= 19.2.0, <= 19.2.5
React Server Dom TurbopackFramework / library
Affected:>= 19.0.0, <= 19.0.5>= 19.1.0, <= 19.1.6>= 19.2.0, <= 19.2.5
React Server Dom WebpackFramework / library
Affected:>= 19.0.0, <= 19.0.5>= 19.1.0, <= 19.1.6>= 19.2.0, <= 19.2.5

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
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed React Server Components packages
    Run 'npm list react-server-dom-webpack react-server-dom-parcel react-server-dom-turbopack' or check package.json dependencies for any of these three packages
    Affected if Any of these three packages appear in installed dependencies
  2. Check the installed version of affected packages
    Run 'npm list react-server-dom-webpack react-server-dom-parcel react-server-dom-turbopack' to see version numbers, then compare against known patched versions from React release notes
    Affected if Installed version has not received the CVE patch (patched versions vary by React release)
  3. Confirm server function endpoint exposure
    Inspect application code and server configuration for HTTP route handlers that expose React Server Component function endpoints (typically paths like '/react/__function' or similar server function routes)
    Affected if HTTP endpoints that invoke React server functions are configured and accessible
  4. Check if application uses Server Actions or Server Functions
    Search codebase for 'use server' directives in component files or function definitions that could be invoked via HTTP requests
    Affected if Server Actions or Server Functions are defined and could receive HTTP requests

Affected if React Server Components packages (react-server-dom-webpack/parcel/turbopack) with unpatched versions are installed AND HTTP-accessible server function endpoints are configured in the application.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to a release after 19.2.5
Interim mitigation

Upgrade affected React packages to patched versions when available, and implement rate limiting or request validation on server function endpoints as a defense-in-depth measure.

Recommended fix Moderate confidence

React 19.3.0 or later (contains patched react-server-dom-* packages)

  1. Upgrade to the latest stable React release (19.3.0 or later) which includes patched versions of react-server-dom-webpack, react-server-dom-parcel, and react-server-dom-turbopack
  2. Run `npm install react@latest react-dom@latest` or `yarn upgrade react react-dom` to update dependencies
  3. If using a framework (Next.js, Remix), ensure it uses the patched React version by checking its dependency requirements
  4. Restart the development server and rebuild production bundles to ensure the patched packages are loaded
  5. Monitor server resource usage after deploying to verify the DoS vulnerability is mitigated
Caveat React 19.x may include breaking changes from previous versions; review React 19 release notes for any incompatibilities with your application code

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in React Server Dom Parcel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-23870 in production — separate from our analysis above.

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.

What this is

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.

What belongs here
  • 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