diff --git a/src/Symfony/Bridge/Monolog/Handler/ChromePhpHandler.php b/src/Symfony/Bridge/Monolog/Handler/ChromePhpHandler.php
index 97ce308983..43f54b536a 100644
--- a/src/Symfony/Bridge/Monolog/Handler/ChromePhpHandler.php
+++ b/src/Symfony/Bridge/Monolog/Handler/ChromePhpHandler.php
@@ -42,7 +42,7 @@ class ChromePhpHandler extends BaseChromePhpHandler
             return;
         }
 
-        if (!preg_match('{\bChrome/\d+[\.\d+]*\b}', $event->getRequest()->headers->get('User-Agent'))) {
+        if (!preg_match('{\b(?:Chrome/\d+(?:\.\d+)*|Firefox/(?:4[3-9]|[5-9]\d|\d{3,})(?:\.\d)*)\b}', $event->getRequest()->headers->get('User-Agent'))) {
             $this->sendHeaders = false;
             $this->headers = array();