CVE-2026-23870 — react-server-dom-parcel
HIGHCVE-2026-23870 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in react-server-dom-parcel. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for react-server-dom-parcel — see the affected versions and patch details below.
Facebook React has a Denial of Service Vulnerability in React Server Components
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-23870.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
react-server-dom-parcelnpmreact-server-dom-turbopacknpmreact-server-dom-webpacknpmDescription
Impact
A denial of service vulnerability could be triggered by sending specially crafted HTTP requests to server function endpoints, this could lead to out-of-memory exceptions or excessive CPU usage.
We recommend updating immediately.
The vulnerability exists in versions 19.0.0 through 19.0.5, 19.1.0 through 19.1.6, and 19.2.0 through 19.2.5 of:
react-server-dom-webpack react-server-dom-parcel react-server-dom-turbopack
Patches
Fixes were back ported to versions 19.0.6, 19.1.7, and 19.2.6.
If you are using any of the above packages please upgrade to any of the fixed versions immediately.
If your app’s React code does not use a server, your app is not affected by this vulnerability. If your app does not use a framework, bundler, or bundler plugin that supports React Server Components, your app is not affected by this vulnerability.
References See the blog post for more information and upgrade instructions.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | react-server-dom-parcel | ≥ 19.0.0&&< 19.0.6 | 19.0.6npm install react-server-dom-parcel@19.0.6 |
| 📦npm | react-server-dom-turbopack | ≥ 19.0.0&&< 19.0.6 | 19.0.6npm install react-server-dom-turbopack@19.0.6 |
| 📦npm | react-server-dom-webpack | ≥ 19.0.0&&< 19.0.6 | 19.0.6npm install react-server-dom-webpack@19.0.6 |
| 📦npm | react-server-dom-parcel | ≥ 19.1.0&&< 19.1.7 | 19.1.7npm install react-server-dom-parcel@19.1.7 |
| 📦npm | react-server-dom-turbopack | ≥ 19.1.0&&< 19.1.7 | 19.1.7npm install react-server-dom-turbopack@19.1.7 |
| 📦npm | react-server-dom-webpack | ≥ 19.1.0&&< 19.1.7 | 19.1.7npm install react-server-dom-webpack@19.1.7 |
Affected Products
react-server-dom-parcelfacebookreact-server-dom-turbopackfacebookreact-server-dom-webpackfacebookResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react-server-dom-parcel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update react-server-dom-parcel to 19.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-23870 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for CVE-2026-23870 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-23870 in your dependencies?
Find it across npm, including transitive dependencies.