diff --git a/common.php b/common.php
index 0d82899..0e377c7 100644
--- a/common.php
+++ b/common.php
@@ -4,6 +4,33 @@
 
 require_once __DIR__ . '/lib/text_sanitize.php';
 
+/**
+ * Read an environment variable (getenv, then $_ENV / $_SERVER).
+ * PHP-FPM often disables putenv(); .env is still loaded into $_ENV.
+ */
+function qdb_env_get(string $name): ?string {
+    $v = getenv($name);
+    if ($v !== false && $v !== '') {
+        return $v;
+    }
+    if (isset($_ENV[$name]) && $_ENV[$name] !== '') {
+        return (string)$_ENV[$name];
+    }
+    if (isset($_SERVER[$name]) && $_SERVER[$name] !== '') {
+        return (string)$_SERVER[$name];
+    }
+    return null;
+}
+
+/** Set an environment variable for the current request (best-effort putenv). */
+function qdb_env_set(string $name, string $value): void {
+    $_ENV[$name] = $value;
+    $_SERVER[$name] = $value;
+    if (function_exists('putenv')) {
+        @putenv("$name=$value");
+    }
+}
+
 /**
  * Load KEY=value pairs from .env in the project root.
  * Does not override variables already set in the real environment.
@@ -37,12 +64,10 @@ function qdb_load_dotenv(string $path): void {
                 $value = substr($value, 1, -1);
             }
         }
-        $existing = getenv($name);
-        if ($existing !== false && $existing !== '') {
+        if (qdb_env_get($name) !== null) {
             continue;
         }
-        putenv("$name=$value");
-        $_ENV[$name] = $value;
+        qdb_env_set($name, $value);
     }
 }
 
@@ -51,8 +76,8 @@ qdb_load_dotenv(__DIR__ . '/.env');
 // --- MASTER-KEY (Server-seitig zum Speichern der DB) ---
 // Per ENV 'QDB_MASTER_KEY' (Base64- oder ASCII-String) oder Fallback auf bisherigen Wert.
 function get_master_key_bytes(): string {
-    $env = getenv('QDB_MASTER_KEY');
-    if (!$env || $env === '') {
+    $env = qdb_env_get('QDB_MASTER_KEY');
+    if ($env === null) {
         throw new RuntimeException('QDB_MASTER_KEY environment variable is not set. Cannot proceed without a master key.');
     }
     $b = base64_decode($env, true);