diff --git a/.travis.yml b/.travis.yml
index 473ef21ccf..088de9fec4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -18,7 +18,7 @@ env:
 matrix:
     include:
         # Use the newer stack for HHVM as HHVM does not support Precise anymore since a long time and so Precise has an outdated version
-        - php: hhvm-3.15
+        - php: hhvm-3.18
           sudo: required
           dist: trusty
           group: edge
diff --git a/src/Symfony/Bundle/SecurityBundle/Tests/Functional/WebTestCase.php b/src/Symfony/Bundle/SecurityBundle/Tests/Functional/WebTestCase.php
index 33da9028a3..da07116ae0 100644
--- a/src/Symfony/Bundle/SecurityBundle/Tests/Functional/WebTestCase.php
+++ b/src/Symfony/Bundle/SecurityBundle/Tests/Functional/WebTestCase.php
@@ -25,7 +25,7 @@ class WebTestCase extends BaseWebTestCase
 
     protected static function deleteTmpDir($testCase)
     {
-        if (!file_exists($dir = sys_get_temp_dir().'/'.Kernel::VERSION.'/'.$testCase)) {
+        if (defined('HHVM_VERSION_ID') || !file_exists($dir = sys_get_temp_dir().'/'.Kernel::VERSION.'/'.$testCase)) {
             return;
         }