diff --git a/packages/vinext/src/build/standalone.ts b/packages/vinext/src/build/standalone.ts
index 25a642c4..9ae05c52 100644
--- a/packages/vinext/src/build/standalone.ts
+++ b/packages/vinext/src/build/standalone.ts
@@ -75,6 +75,21 @@ function resolvePackageJsonPath(packageName: string, resolver: NodeRequire): str
   try {
     return resolver.resolve(`${packageName}/package.json`);
   } catch {
+    // Some packages only expose subpath exports (for example `rsc-html-stream`,
+    // which exports `./server` but not `.` or `./package.json`). resolver.resolve()
+    // cannot access those hidden paths, but Node still exposes the installed
+    // node_modules lookup locations via resolve.paths().
+    const lookupPaths = resolver.resolve.paths(packageName) ?? [];
+    for (const lookupPath of lookupPaths) {
+      const candidate = path.join(lookupPath, packageName, "package.json");
+      if (fs.existsSync(candidate)) {
+        const pkg = readPackageJson(candidate);
+        if (pkg.name === packageName) {
+          return candidate;
+        }
+      }
+    }
+
     // Some packages do not export ./package.json via exports map.
     // Fallback: resolve package entry and walk up to the nearest matching package.json.
     try {
diff --git a/packages/vinext/src/plugins/server-externals-manifest.ts b/packages/vinext/src/plugins/server-externals-manifest.ts
index 732dc40b..cf4b488d 100644
--- a/packages/vinext/src/plugins/server-externals-manifest.ts
+++ b/packages/vinext/src/plugins/server-externals-manifest.ts
@@ -1,7 +1,14 @@
 import fs from "node:fs";
 import path from "node:path";
+import { builtinModules } from "node:module";
 import type { Plugin } from "vite";
 
+const BUILTIN_MODULES = new Set(
+  builtinModules.flatMap((name) =>
+    name.startsWith("node:") ? [name, name.slice(5)] : [name, `node:${name}`],
+  ),
+);
+
 /**
  * Extract the npm package name from a bare module specifier.
  *
@@ -11,16 +18,23 @@ import type { Plugin } from "vite";
  *  - Node built-ins ("node:fs")
  *  - Package self-references ("#imports")
  */
-function packageNameFromSpecifier(specifier: string): string | null {
+export function packageNameFromSpecifier(specifier: string): string | null {
   if (
+    !specifier ||
     specifier.startsWith(".") ||
     specifier.startsWith("/") ||
-    specifier.startsWith("node:") ||
+    specifier.startsWith("\\") ||
     specifier.startsWith("#")
   ) {
     return null;
   }
 
+  // External specifiers can include non-package schemes such as
+  // "virtual:vite-rsc" or "file:...". Those are never npm packages.
+  if (/^[a-zA-Z][a-zA-Z\d+.-]*:/.test(specifier)) {
+    return null;
+  }
+
   if (specifier.startsWith("@")) {
     const parts = specifier.split("/");
     if (parts.length >= 2) {
@@ -29,7 +43,11 @@ function packageNameFromSpecifier(specifier: string): string | null {
     return null;
   }
 
-  return specifier.split("/")[0] || null;
+  const packageName = specifier.split("/")[0] || null;
+  if (!packageName || BUILTIN_MODULES.has(specifier) || BUILTIN_MODULES.has(packageName)) {
+    return null;
+  }
+  return packageName;
 }
 
 /**
@@ -95,6 +113,7 @@ export function createServerExternalsManifestPlugin(): Plugin {
           outDir = path.basename(dir) === "server" ? dir : path.dirname(dir);
         }
 
+        const bundleFiles = new Set(Object.keys(bundle));
         for (const item of Object.values(bundle)) {
           if (item.type !== "chunk") continue;
           // In Rollup output, item.imports normally contains filenames of other
@@ -104,6 +123,9 @@ export function createServerExternalsManifestPlugin(): Plugin {
           // filenames (relative/absolute paths) and extracts the package name from
           // bare specifiers — which is exactly what the standalone BFS needs.
           for (const specifier of [...item.imports, ...item.dynamicImports]) {
+            if (bundleFiles.has(specifier)) {
+              continue;
+            }
             const pkg = packageNameFromSpecifier(specifier);
             if (pkg) externals.add(pkg);
           }
diff --git a/tests/server-externals-manifest.test.ts b/tests/server-externals-manifest.test.ts
new file mode 100644
index 00000000..b0d2055b
--- /dev/null
+++ b/tests/server-externals-manifest.test.ts
@@ -0,0 +1,53 @@
+import { describe, expect, it } from "vite-plus/test";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { createServerExternalsManifestPlugin } from "../packages/vinext/src/plugins/server-externals-manifest.js";
+
+describe("createServerExternalsManifestPlugin", () => {
+  it("ignores bundle files, virtual modules, and node builtins when writing the manifest", () => {
+    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "vinext-externals-manifest-"));
+    const outDir = path.join(tmpDir, "dist", "server");
+    fs.mkdirSync(outDir, { recursive: true });
+
+    try {
+      const plugin = createServerExternalsManifestPlugin();
+      const writeBundle = (plugin.writeBundle as { handler: Function }).handler;
+
+      writeBundle.call(
+        { environment: { name: "ssr" } },
+        { dir: outDir },
+        {
+          "index.js": {
+            type: "chunk",
+            imports: [
+              "react",
+              "@scope/pkg/subpath",
+              "ipaddr.js",
+              "index.js",
+              "assets/chunk-abc.js",
+              "virtual:vite-rsc",
+              "crypto",
+              "fs/promises",
+              "node:path",
+            ],
+            dynamicImports: ["react-dom/server.edge"],
+          },
+          "assets/chunk-abc.js": {
+            type: "chunk",
+            imports: [],
+            dynamicImports: [],
+          },
+        },
+      );
+
+      const manifest = JSON.parse(
+        fs.readFileSync(path.join(outDir, "vinext-externals.json"), "utf-8"),
+      ) as string[];
+
+      expect(manifest.sort()).toEqual(["@scope/pkg", "ipaddr.js", "react", "react-dom"].sort());
+    } finally {
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    }
+  });
+});
diff --git a/tests/standalone-build.test.ts b/tests/standalone-build.test.ts
index bd1691e1..a7ec156c 100644
--- a/tests/standalone-build.test.ts
+++ b/tests/standalone-build.test.ts
@@ -398,6 +398,54 @@ describe("emitStandaloneOutput", () => {
     ).toBe(true);
   });
 
+  it("copies vinext runtime dependencies that only expose subpath exports", () => {
+    const appRoot = path.join(tmpDir, "app");
+    fs.mkdirSync(appRoot, { recursive: true });
+
+    writeFile(appRoot, "package.json", JSON.stringify({ name: "app" }, null, 2));
+    writeFile(appRoot, "dist/client/assets/main.js", "console.log('client');\n");
+    writeFile(appRoot, "dist/server/entry.js", 'console.log("server");\n');
+    writeFile(appRoot, "dist/server/vinext-externals.json", JSON.stringify([]));
+
+    const fakeVinextRoot = path.join(tmpDir, "fake-vinext");
+    writeFile(
+      fakeVinextRoot,
+      "package.json",
+      JSON.stringify(
+        {
+          name: "vinext",
+          version: "0.0.0-test",
+          type: "module",
+          dependencies: {
+            "rsc-html-stream": "1.0.0",
+          },
+        },
+        null,
+        2,
+      ),
+    );
+    writeFile(
+      fakeVinextRoot,
+      "dist/server/prod-server.js",
+      "export async function startProdServer() {}\n",
+    );
+    writePackage(fakeVinextRoot, "rsc-html-stream", {}, { exports: { "./server": "./server.js" } });
+    writeFile(fakeVinextRoot, "node_modules/rsc-html-stream/server.js", "export {};\n");
+
+    const result = emitStandaloneOutput({
+      root: appRoot,
+      outDir: path.join(appRoot, "dist"),
+      vinextPackageRoot: fakeVinextRoot,
+    });
+
+    expect(result.copiedPackages).toContain("rsc-html-stream");
+    expect(
+      fs.existsSync(
+        path.join(appRoot, "dist/standalone/node_modules/rsc-html-stream/package.json"),
+      ),
+    ).toBe(true);
+  });
+
   it("copies packages referenced through symlinked node_modules entries", () => {
     const appRoot = path.join(tmpDir, "app");
     fs.mkdirSync(appRoot, { recursive: true });