diff --git a/src/Symfony/Component/Process/Process.php b/src/Symfony/Component/Process/Process.php
index d5c697cf9c2d7..f3f738c5484f2 100644
--- a/src/Symfony/Component/Process/Process.php
+++ b/src/Symfony/Component/Process/Process.php
@@ -339,9 +339,11 @@ public function start(callable $callback = null, array $env = [])
         }
 
         $envPairs = [];
-        foreach ($env as $k => $v) {
-            if (false !== $v && 'argc' !== $k && 'argv' !== $k) {
-                $envPairs[] = $k.'='.$v;
+        if(\is_array($env)){
+            foreach ($env as $k => $v) {
+                if (false !== $v && 'argc' !== $k && 'argv' !== $k) {
+                    $envPairs[] = $k.'='.$v;
+                }
             }
         }