diff --git a/src/io-util.ts b/src/io-util.ts
index 89709f3..fd3a3e1 100644
--- a/src/io-util.ts
+++ b/src/io-util.ts
@@ -167,8 +167,12 @@ function normalizeSeparators(p: string): string {
 function isUnixExecutable(stats: fs.Stats): boolean {
   return (
     (stats.mode & 1) > 0 ||
-    ((stats.mode & 8) > 0 && stats.gid === process.getgid()) ||
-    ((stats.mode & 64) > 0 && stats.uid === process.getuid())
+    ((stats.mode & 8) > 0 &&
+      process.getgid !== undefined &&
+      stats.gid === process.getgid()) ||
+    ((stats.mode & 64) > 0 &&
+      process.getuid !== undefined &&
+      stats.uid === process.getuid())
   )
 }