diff --git a/dist/setup/index.js b/dist/setup/index.js
index be406fc6..f06d22c9 100644
--- a/dist/setup/index.js
+++ b/dist/setup/index.js
@@ -99685,13 +99685,15 @@ function resolveVersionInput() {
 function getNameFromPackageManagerField() {
     var _a, _b;
     // Check devEngines.packageManager and packageManager field in package.json
+    const SUPPORTED_PACKAGE_MANAGERS = ['npm', 'yarn', 'pnpm'];
     try {
-        const packageJson = JSON.parse(fs_1.default.readFileSync('package.json', 'utf-8'));
+        const packageJson = JSON.parse(fs_1.default.readFileSync(path.join(process.env.GITHUB_WORKSPACE, 'package.json'), 'utf-8'));
         return (((_b = (_a = packageJson.devEngines) === null || _a === void 0 ? void 0 : _a.packageManager) === null || _b === void 0 ? void 0 : _b.name) ||
             (() => {
                 const pm = packageJson.packageManager;
                 if (typeof pm === 'string') {
-                    const match = pm.match(/^(?:\^)?(npm|yarn|pnpm)@/);
+                    const regex = new RegExp(`^(?:\\^)?(${SUPPORTED_PACKAGE_MANAGERS.join('|')})@`);
+                    const match = pm.match(regex);
                     return match ? match[1] : undefined;
                 }
                 return undefined;
diff --git a/src/main.ts b/src/main.ts
index e58d95bc..0b622102 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -128,14 +128,23 @@ function resolveVersionInput(): string {
 
 export function getNameFromPackageManagerField(): string | undefined {
   // Check devEngines.packageManager and packageManager field in package.json
+  const SUPPORTED_PACKAGE_MANAGERS = ['npm', 'yarn', 'pnpm'];
   try {
-    const packageJson = JSON.parse(fs.readFileSync('package.json', 'utf-8'));
+    const packageJson = JSON.parse(
+      fs.readFileSync(
+        path.join(process.env.GITHUB_WORKSPACE!, 'package.json'),
+        'utf-8'
+      )
+    );
     return (
       packageJson.devEngines?.packageManager?.name ||
       (() => {
         const pm = packageJson.packageManager;
         if (typeof pm === 'string') {
-          const match = pm.match(/^(?:\^)?(npm|yarn|pnpm)@/);
+          const regex = new RegExp(
+            `^(?:\\^)?(${SUPPORTED_PACKAGE_MANAGERS.join('|')})@`
+          );
+          const match = pm.match(regex);
           return match ? match[1] : undefined;
         }
         return undefined;