diff --git a/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler/Deprecation.php b/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler/Deprecation.php
index baedeca346..650c8a1543 100644
--- a/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler/Deprecation.php
+++ b/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler/Deprecation.php
@@ -60,7 +60,9 @@ class Deprecation
         $line = $trace[$i];
         $this->triggeringFile = $file;
         if (isset($line['object']) || isset($line['class'])) {
+            set_error_handler(function () {});
             $parsedMsg = @unserialize($this->message);
+            restore_error_handler();
             if ($parsedMsg && isset($parsedMsg['deprecation'])) {
                 $this->message = $parsedMsg['deprecation'];
                 $this->originClass = $parsedMsg['class'];