diff --git a/admin/test-bad-package/README.mdx b/admin/test-bad-package/README.mdx
index 40abc5448c2b..260522db2417 100644
--- a/admin/test-bad-package/README.mdx
+++ b/admin/test-bad-package/README.mdx
@@ -12,7 +12,7 @@ import {version as ReactVersion} from 'react';
 import {version as ReactDOMVersion} from 'react-dom';
 
 export function TestComponent() {
-  const expectedVersion = 18;
+  const expectedVersion = 19;
   if (!ReactVersion.startsWith(`${expectedVersion}`)) {
     throw new Error(
       `'test-bad-package/README.mdx' is rendered with bad React version: ${ReactVersion}`,
diff --git a/packages/docusaurus/src/webpack/base.ts b/packages/docusaurus/src/webpack/base.ts
index 3ffda658fedd..4dce834d9075 100644
--- a/packages/docusaurus/src/webpack/base.ts
+++ b/packages/docusaurus/src/webpack/base.ts
@@ -35,14 +35,19 @@ const LibrariesToTranspileRegex = new RegExp(
   LibrariesToTranspile.map((libName) => `(node_modules/${libName})`).join('|'),
 );
 
-const ReactAliases: Record<string, string> = process.env
-  .DOCUSAURUS_NO_REACT_ALIASES
-  ? {}
-  : {
-      react: path.dirname(require.resolve('react/package.json')),
-      'react-dom': path.dirname(require.resolve('react-dom/package.json')),
-      '@mdx-js/react': path.dirname(require.resolve('@mdx-js/react')),
-    };
+function getReactAliases(siteDir: string): Record<string, string> {
+  // Escape hatch
+  if (process.env.DOCUSAURUS_NO_REACT_ALIASES) {
+    return {};
+  }
+  const resolveSitePkg = (id: string) =>
+    require.resolve(id, {paths: [siteDir]});
+  return {
+    react: path.dirname(resolveSitePkg('react/package.json')),
+    'react-dom': path.dirname(resolveSitePkg('react-dom/package.json')),
+    '@mdx-js/react': path.dirname(resolveSitePkg('@mdx-js/react')),
+  };
+}
 
 export function excludeJS(modulePath: string): boolean {
   // Always transpile client dir
@@ -186,7 +191,7 @@ export async function createBaseConfig({
         process.cwd(),
       ],
       alias: {
-        ...ReactAliases,
+        ...getReactAliases(siteDir),
         '@site': siteDir,
         '@generated': generatedFilesDir,
         ...(await loadDocusaurusAliases()),
diff --git a/website/package.json b/website/package.json
index fc61ef63ae06..4f1442b77001 100644
--- a/website/package.json
+++ b/website/package.json
@@ -58,8 +58,8 @@
     "netlify-plugin-cache": "^1.0.3",
     "pure-react-carousel": "^1.30.1",
     "raw-loader": "^4.0.2",
-    "react": "^18.0.0",
-    "react-dom": "^18.0.0",
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0",
     "react-lite-youtube-embed": "^2.3.52",
     "react-medium-image-zoom": "^5.1.6",
     "recma-mdx-displayname": "^0.4.1",