diff --git a/packages/vite/src/node/config.ts b/packages/vite/src/node/config.ts
index e63877c1698f17..d42af1a6a74a3b 100644
--- a/packages/vite/src/node/config.ts
+++ b/packages/vite/src/node/config.ts
@@ -928,7 +928,8 @@ export async function loadConfigFromFile(
     // check package.json for type: "module" and set `isESM` to true
     try {
       const pkg = lookupFile(configRoot, ['package.json'])
-      isESM = !!pkg && JSON.parse(pkg).type === 'module'
+      isESM =
+        !!pkg && JSON.parse(fs.readFileSync(pkg, 'utf-8')).type === 'module'
     } catch (e) {}
   }
 
diff --git a/packages/vite/src/node/env.ts b/packages/vite/src/node/env.ts
index 338de6784497d8..374e1f049c0618 100644
--- a/packages/vite/src/node/env.ts
+++ b/packages/vite/src/node/env.ts
@@ -1,7 +1,8 @@
 import fs from 'node:fs'
+import path from 'node:path'
 import { parse } from 'dotenv'
 import { expand } from 'dotenv-expand'
-import { arraify, lookupFile } from './utils'
+import { arraify, tryStatSync } from './utils'
 import type { UserConfig } from './config'
 
 export function loadEnv(
@@ -26,12 +27,10 @@ export function loadEnv(
 
   const parsed = Object.fromEntries(
     envFiles.flatMap((file) => {
-      const path = lookupFile(envDir, [file], {
-        pathOnly: true,
-        rootDir: envDir,
-      })
-      if (!path) return []
-      return Object.entries(parse(fs.readFileSync(path)))
+      const filePath = path.join(envDir, file)
+      if (!tryStatSync(filePath)?.isFile()) return []
+
+      return Object.entries(parse(fs.readFileSync(filePath)))
     }),
   )
 
diff --git a/packages/vite/src/node/optimizer/index.ts b/packages/vite/src/node/optimizer/index.ts
index 496664baf8897a..b5a052c75f5c77 100644
--- a/packages/vite/src/node/optimizer/index.ts
+++ b/packages/vite/src/node/optimizer/index.ts
@@ -1199,13 +1199,10 @@ const lockfileFormats = [
   { name: 'pnpm-lock.yaml', checkPatches: false }, // Included in lockfile
   { name: 'bun.lockb', checkPatches: true },
 ]
+const lockfileNames = lockfileFormats.map((l) => l.name)
 
 export function getDepHash(config: ResolvedConfig, ssr: boolean): string {
-  const lockfilePath = lookupFile(
-    config.root,
-    lockfileFormats.map((l) => l.name),
-    { pathOnly: true },
-  )
+  const lockfilePath = lookupFile(config.root, lockfileNames)
   let content = lockfilePath ? fs.readFileSync(lockfilePath, 'utf-8') : ''
   if (lockfilePath) {
     const lockfileName = path.basename(lockfilePath)
diff --git a/packages/vite/src/node/ssr/ssrExternal.ts b/packages/vite/src/node/ssr/ssrExternal.ts
index 6644fdd8e2e0b4..3d8185dad88080 100644
--- a/packages/vite/src/node/ssr/ssrExternal.ts
+++ b/packages/vite/src/node/ssr/ssrExternal.ts
@@ -216,7 +216,11 @@ function cjsSsrCollectExternals(
   seen: Set<string>,
   logger: Logger,
 ) {
-  const rootPkgContent = lookupFile(root, ['package.json'])
+  const rootPkgPath = lookupFile(root, ['package.json'])
+  if (!rootPkgPath) {
+    return
+  }
+  const rootPkgContent = fs.readFileSync(rootPkgPath, 'utf-8')
   if (!rootPkgContent) {
     return
   }
diff --git a/packages/vite/src/node/utils.ts b/packages/vite/src/node/utils.ts
index 81d7e22bad6cf8..78b71a512705dd 100644
--- a/packages/vite/src/node/utils.ts
+++ b/packages/vite/src/node/utils.ts
@@ -387,28 +387,20 @@ export function tryStatSync(file: string): fs.Stats | undefined {
     // Ignore errors
   }
 }
-interface LookupFileOptions {
-  pathOnly?: boolean
-  rootDir?: string
-}
 
 export function lookupFile(
   dir: string,
-  formats: string[],
-  options?: LookupFileOptions,
+  fileNames: string[],
 ): string | undefined {
-  for (const format of formats) {
-    const fullPath = path.join(dir, format)
-    if (tryStatSync(fullPath)?.isFile()) {
-      return options?.pathOnly ? fullPath : fs.readFileSync(fullPath, 'utf-8')
+  while (dir) {
+    for (const fileName of fileNames) {
+      const fullPath = path.join(dir, fileName)
+      if (tryStatSync(fullPath)?.isFile()) return fullPath
     }
-  }
-  const parentDir = path.dirname(dir)
-  if (
-    parentDir !== dir &&
-    (!options?.rootDir || parentDir.startsWith(options?.rootDir))
-  ) {
-    return lookupFile(parentDir, formats, options)
+    const parentDir = path.dirname(dir)
+    if (parentDir === dir) return
+
+    dir = parentDir
   }
 }