Answer in brief
CVE-2026-126187 records a Critical severity (CVSS 9.5) vulnerability in React: Unauthenticated Remote Code Execution in React Server Components. The current sources do not mark it as known exploited. The current feed maps react/react (generic), react-server-dom-parcel (npm), react-server-dom-parcel (npm), react-server-dom-parcel (npm) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps react/react (generic), react-server-dom-parcel (npm), react-server-dom-parcel (npm), react-server-dom-parcel (npm) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| react/reactgeneric | >=19.0.0 <19.0.9 || >=19.1.0 <19.1.10 || >=19.2.0 <19.2.9 || >=19.3.0 <19.3.1 | 19.0.9, 19.1.10, 19.2.9, 19.3.1 |
| react-server-dom-parcelnpm | >=19.0.0,<19.0.9 | 19.0.9 |
| react-server-dom-parcelnpm | >=19.3.0,<19.3.1 | 19.3.1 |
| react-server-dom-parcelnpm | >=19.2.0,<19.2.9 | 19.2.9 |
| react-server-dom-parcelnpm | >=19.1.0,<19.1.10 | 19.1.10 |
| react-server-dom-parcelnpm | >=19.0.0 <19.0.9 | 19.0.9 |
| react-server-dom-parcelnpm | >=19.1.0 <19.1.10 | 19.1.10 |
| react-server-dom-parcelnpm | >=19.2.0 <19.2.9 | 19.2.9 |
| react-server-dom-parcelnpm | >=19.3.0 <19.3.1 | 19.3.1 |
| react-server-dom-turbopacknpm | >=19.0.0,<19.0.9 | 19.0.9 |
| react-server-dom-turbopacknpm | >=19.2.0,<19.2.9 | 19.2.9 |
| react-server-dom-turbopacknpm | >=19.1.0,<19.1.10 | 19.1.10 |
| react-server-dom-turbopacknpm | >=19.3.0,<19.3.1 | 19.3.1 |
| react-server-dom-turbopacknpm | >=19.0.0 <19.0.9 | 19.0.9 |
| react-server-dom-turbopacknpm | >=19.1.0 <19.1.10 | 19.1.10 |
| react-server-dom-turbopacknpm | >=19.2.0 <19.2.9 | 19.2.9 |
| react-server-dom-turbopacknpm | >=19.3.0 <19.3.1 | 19.3.1 |
| react-server-dom-webpacknpm | >=19.3.0,<19.3.1 | 19.3.1 |
| react-server-dom-webpacknpm | >=19.2.0,<19.2.9 | 19.2.9 |
| react-server-dom-webpacknpm | >=19.1.0,<19.1.10 | 19.1.10 |
| react-server-dom-webpacknpm | >=19.0.0,<19.0.9 | 19.0.9 |
| react-server-dom-webpacknpm | >=19.0.0 <19.0.9 | 19.0.9 |
| react-server-dom-webpacknpm | >=19.1.0 <19.1.10 | 19.1.10 |
| react-server-dom-webpacknpm | >=19.2.0 <19.2.9 | 19.2.9 |
| react-server-dom-webpacknpm | >=19.3.0 <19.3.1 | 19.3.1 |
Published upstream
Nov 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 10, 2026
React is a JavaScript library for building user interfaces. From 19.0.0 until 19.0.9, 19.1.10, 19.2.9, and 19.3.1, the react-server-dom-webpack, react-server-dom-parcel, and react-server-dom-turbopack packages are vulnerable to unauthenticated remote code execution through crafted payloads targeting frameworks that support React Server Components. The vulnerability only affects extremely rare cases where responses transport multiple typed arrays and an attacker-controlled value. Applications whose React code does not use a server are not affected. Applications that do not use a framework, bundler, or bundler plugin that supports React Server Components are not affected. This issue is fixed in versions 19.0.9, 19.1.10, 19.2.9, and 19.3.1.
Quoted source text, attributed separately from HOL analysis.