From a7c75c6328e7dc1e4b3f8c35b323a521a3b34eb8 Mon Sep 17 00:00:00 2001
From: Marcus Bointon <marcus@synchromedia.co.uk>
Date: Wed, 30 Oct 2019 18:21:19 +0100
Subject: [PATCH] Make background attribute pattern match more precise, see
 #1877

---
 src/PHPMailer.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/PHPMailer.php b/src/PHPMailer.php
index 1b203622..49b2308d 100644
--- a/src/PHPMailer.php
+++ b/src/PHPMailer.php
@@ -3975,7 +3975,7 @@ class PHPMailer
      */
     public function msgHTML($message, $basedir = '', $advanced = false)
     {
-        preg_match_all('/(src|background)=["\'](.*)["\']/Ui', $message, $images);
+        preg_match_all('/\s(src|background)=["\'](.*)["\']/Ui', $message, $images);
         if (array_key_exists(2, $images)) {
             if (strlen($basedir) > 1 && '/' !== substr($basedir, -1)) {
                 // Ensure $basedir has a trailing /