Merge pull request PHPOffice#1338 from pcworld/image-security-doc

Improve security-related documentation of addImage and addHtml

docs/elements.rst

@@ -242,7 +242,7 @@ To add an image, use the ``addImage`` method to sections, headers, footers, text
 
     $section->addImage($src, [$style]);
 
-- ``$src``. String path to a local image, URL of a remote image or the image data, as a string.
+- ``$src``. String path to a local image, URL of a remote image or the image data, as a string. Warning: Do not pass user-generated strings here, as that would allow an attacker to read arbitrary files or perform server-side request forgery by passing file paths or URLs instead of image data.
 - ``$style``. See :ref:`image-style`.
 
 Examples:

src/PhpWord/Shared/Html.php

@@ -37,6 +37,8 @@ class Html
      * Add HTML parts.
      *
      * Note: $stylesheet parameter is removed to avoid PHPMD error for unused parameter
+     * Warning: Do not pass user-generated HTML here, as that would allow an attacker to read arbitrary
+     * files or perform server-side request forgery by passing local file paths or URLs in <img>.
      *
      * @param \PhpOffice\PhpWord\Element\AbstractContainer $element Where the parts need to be added
      * @param string $html The code to parse