diff --git a/src/aphront/sink/base/AphrontHTTPSink.php b/src/aphront/sink/base/AphrontHTTPSink.php
index 1b1d537ecd..417085ad56 100644
--- a/src/aphront/sink/base/AphrontHTTPSink.php
+++ b/src/aphront/sink/base/AphrontHTTPSink.php
@@ -88,6 +88,7 @@ abstract class AphrontHTTPSink {
     }
 
     foreach ($headers as $header) {
+      list($name, $value) = $header;
       $this->emitHeader($name, $value);
     }
   }