diff --git a/.changeset/fix-json-import-attribute-stripped.md b/.changeset/fix-json-import-attribute-stripped.md
new file mode 100644
index 00000000..a4ca1b6f
--- /dev/null
+++ b/.changeset/fix-json-import-attribute-stripped.md
@@ -0,0 +1,19 @@
+---
+"@create-node-app/core": patch
+---
+
+Fix dependencies declared in a template's or extension's `package.json` being
+silently dropped during scaffolding.
+
+`importIfExists` loaded `.json` files via a dynamic `import()` with a
+`with { type: "json" }` attribute. Although valid at the source level,
+tsup/esbuild strips the attribute when bundling, so the published `dist`
+contained a bare `import("…json")`. On Node >= 20.10 that throws
+`ERR_IMPORT_ATTRIBUTE_MISSING`, and the surrounding `try/catch` swallowed it —
+so every dependency coming from a static `package.json` (i.e. almost every
+extension) vanished from the generated project, breaking type-check/build.
+
+JSON manifests are now read with `readFileSync` + `JSON.parse`, which is immune
+to bundler transforms and works across Node versions. Added a regression test
+that asserts dependencies from both `package.json` and `package/index.js` are
+merged into the installable result.
diff --git a/packages/create-node-app-core/package.ts b/packages/create-node-app-core/package.ts
index 0c7a5953..f78c1110 100644
--- a/packages/create-node-app-core/package.ts
+++ b/packages/create-node-app-core/package.ts
@@ -1,7 +1,6 @@
 // Removed unused eslint-disable (global-require) after migration to flat config
-import { existsSync } from "fs";
+import { existsSync, readFileSync } from "fs";
 import { createRequire } from "node:module";
-import { pathToFileURL } from "node:url";
 import merge from "lodash.merge";
 import type { TemplateOrExtension } from "./loaders.js";
 import { getPackagePath } from "./paths.js";
@@ -37,20 +36,22 @@ const localRequire = createRequire(import.meta.url);
 /**
  * Load a module from disk if it exists. Throws if missing.
  *
- * For `.json` files we use dynamic `import()` with the `with { type: "json" }`
- * assertion (Node 22+). For `.js`/`.cjs` files we use `createRequire`. This
- * avoids the legacy `require()` pattern that only works because of tsup's
- * `--shims` build flag.
+ * For `.json` files we read the file and `JSON.parse` it. We deliberately avoid
+ * a dynamic `import()` with an import attribute (`with { type: "json" }`):
+ * although valid at the source level, tsup/esbuild strips the attribute when
+ * bundling, producing a bare `import("...json")` in the published `dist`. On
+ * Node >= 20.10 that throws `ERR_IMPORT_ATTRIBUTE_MISSING`, which the callers
+ * swallow — silently dropping every dependency declared in a template's or
+ * extension's `package.json`. Reading + parsing is bundler- and Node-agnostic.
+ *
+ * For `.js`/`.cjs` files (e.g. `package/index.js`) we use `createRequire`.
  */
 const importIfExists = async (filePath: string): Promise<unknown> => {
   if (!existsSync(filePath)) {
     throw new Error(`File ${filePath} does not exist`);
   }
   if (filePath.endsWith(".json")) {
-    const mod = (await import(pathToFileURL(filePath).href, {
-      with: { type: "json" },
-    })) as { default?: unknown };
-    return mod.default ?? mod;
+    return JSON.parse(readFileSync(filePath, "utf8"));
   }
   // Fallback to createRequire for JS/CJS template modules.
   return localRequire(filePath);
diff --git a/packages/create-node-app-core/tests/package.test.mts b/packages/create-node-app-core/tests/package.test.mts
new file mode 100644
index 00000000..20cfad50
--- /dev/null
+++ b/packages/create-node-app-core/tests/package.test.mts
@@ -0,0 +1,88 @@
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import { pathToFileURL } from "node:url";
+import { tmpdir } from "node:os";
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from "node:fs";
+import path from "node:path";
+
+import { loadPackages } from "../package.js";
+
+const safeRm = (d: string) => {
+  try {
+    rmSync(d, { recursive: true, force: true });
+  } catch {
+    // ignore
+  }
+};
+
+/**
+ * Regression test for the bundler-stripped JSON import attribute.
+ *
+ * `importIfExists` used to load `package.json` via a dynamic `import()` with a
+ * `with { type: "json" }` attribute. tsup/esbuild stripped the attribute in the
+ * published `dist`, so on Node >= 20.10 the import threw and the surrounding
+ * `try/catch` swallowed it — silently dropping every dependency declared in a
+ * template's or extension's `package.json`.
+ *
+ * This test asserts that dependencies coming from a static `package.json`
+ * (extension) and from a `package/index.js` module (template) are both present
+ * in the merged, installable result.
+ */
+test("loadPackages merges dependencies from package.json and package/index.js", async () => {
+  const root = mkdtempSync(path.join(tmpdir(), "cna-loadpkg-"));
+  try {
+    // Template exposes its manifest through package/index.js (resolved via require).
+    const templateDir = path.join(root, "template");
+    mkdirSync(path.join(templateDir, "package"), { recursive: true });
+    writeFileSync(
+      path.join(templateDir, "package", "index.js"),
+      `module.exports = function resolvePackage(_setup, { appName }) {
+        return {
+          name: appName,
+          scripts: { build: "tsc" },
+          dependencies: { react: "^19.0.0" },
+          devDependencies: { typescript: "^5.0.0" },
+        };
+      };\n`,
+    );
+
+    // Extension declares its dependencies through a static package.json.
+    const extensionDir = path.join(root, "extension");
+    mkdirSync(extensionDir, { recursive: true });
+    writeFileSync(
+      path.join(extensionDir, "package.json"),
+      JSON.stringify({
+        name: "example-extension",
+        dependencies: { "@tanstack/react-query": "^5.0.0" },
+        devDependencies: { vitest: "^3.0.0" },
+      }),
+    );
+
+    const result = (await loadPackages({
+      appName: "my-app",
+      templatesOrExtensions: [
+        { url: pathToFileURL(templateDir).toString() },
+        { url: pathToFileURL(extensionDir).toString() },
+      ],
+    })) as { dependencies: string[]; devDependencies: string[] };
+
+    assert.ok(
+      result.dependencies.includes("react@^19.0.0"),
+      "template dependency should be present",
+    );
+    assert.ok(
+      result.dependencies.includes("@tanstack/react-query@^5.0.0"),
+      "extension dependency from package.json should be merged (regression)",
+    );
+    assert.ok(
+      result.devDependencies.includes("typescript@^5.0.0"),
+      "template devDependency should be present",
+    );
+    assert.ok(
+      result.devDependencies.includes("vitest@^3.0.0"),
+      "extension devDependency from package.json should be merged (regression)",
+    );
+  } finally {
+    safeRm(root);
+  }
+});