diff --git a/lib/manager/composer/artifacts.ts b/lib/manager/composer/artifacts.ts
index 76835c836e54278f305f58d64bd089bb5a732d32..7a4aaecde405344ae7a93a7797bc633a6b7feb87 100644
--- a/lib/manager/composer/artifacts.ts
+++ b/lib/manager/composer/artifacts.ts
@@ -105,9 +105,8 @@ export async function updateArtifacts({
     if (authJson) {
       await writeLocalFile('auth.json', JSON.stringify(authJson));
     }
-    const cwd = getSubDirectory(packageFileName);
     const execOptions: ExecOptions = {
-      cwd,
+      cwdFile: packageFileName,
       extraEnv: {
         COMPOSER_CACHE_DIR: cacheDir,
       },