CVE-2026-23864
HIGHCVE-2026-23864 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in react-server-dom-parcel. O3 Security confirms whether CVE-2026-23864 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
React Server Components have multiple Denial of Service Vulnerabilities
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
react-server-dom-parcelnpmreact-server-dom-turbopacknpmreact-server-dom-webpacknpmDescription
Multiple denial of service vulnerabilities exist in React Server Components, affecting the following packages: react-server-dom-parcel, react-server-dom-turbopack, react-server-dom-webpack.
The vulnerabilities are triggered by sending specially crafted HTTP requests to Server Function endpoints, and could lead to server crashes, out-of-memory exceptions or excessive CPU usage; depending on the vulnerable code path being exercised, the application configuration and application code.
Strongly consider upgrading to the latest package versions to reduce risk and prevent availability issues in applications using React Server Components.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | react-server-dom-parcel | ≥ 19.0.0&&< 19.0.4 | 19.0.4 |
| 📦npm | react-server-dom-turbopack | ≥ 19.1.0-canary-7130d0c6-20241212&&< 19.1.5 | 19.1.5 |
| 📦npm | react-server-dom-webpack | ≥ 19.2.0-canary-63779030-20250328&&< 19.2.4 | 19.2.4 |
| 📦npm | react-server-dom-turbopack | ≥ 19.0.0&&< 19.0.4 | 19.0.4 |
| 📦npm | react-server-dom-parcel | ≥ 19.1.0-canary-7130d0c6-20241212&&< 19.1.5 | 19.1.5 |
| 📦npm | react-server-dom-parcel | ≥ 19.2.0-canary-63779030-20250328&&< 19.2.4 | 19.2.4 |
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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update react-server-dom-parcel to 19.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-23864 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-23864 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-23864. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-23864 in your dependencies?
O3 detects CVE-2026-23864 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.