diff --git a/src/Composer/EventDispatcher/EventDispatcher.php b/src/Composer/EventDispatcher/EventDispatcher.php
index cd815112b..4a5656d9f 100644
--- a/src/Composer/EventDispatcher/EventDispatcher.php
+++ b/src/Composer/EventDispatcher/EventDispatcher.php
@@ -257,9 +257,9 @@ class EventDispatcher
             throw new \RuntimeException('Failed to locate PHP binary to execute '.$scriptName);
         }
 
-        $allowUrlFOpenFlag = ' -d allow_url_fopen=' . ini_get('allow_url_fopen');
-        $disableFunctionsFlag = ' -d disable_functions="' . ini_get('disable_functions') . '"';
-        $memoryLimitFlag = ' -d memory_limit=' . ini_get('memory_limit');
+        $allowUrlFOpenFlag = ' -d allow_url_fopen=' . ProcessExecutor::escape(ini_get('allow_url_fopen'));
+        $disableFunctionsFlag = ' -d disable_functions=' . ProcessExecutor::escape(ini_get('disable_functions'));
+        $memoryLimitFlag = ' -d memory_limit=' . ProcessExecutor::escape(ini_get('memory_limit'));
 
         return ProcessExecutor::escape($phpPath) . $allowUrlFOpenFlag . $disableFunctionsFlag . $memoryLimitFlag;
     }