Bug #77074 [Opn]: XSS through error messages

Edit report at https://bugs.php.net/bug.php?id=77074&edit=1 ID: 77074 Updated by: nikic@php.net Reported by: david at grudl dot com Summary: XSS through error messages Status: Open Type: Bug Package: Output Control PHP Version: 7.3.0RC4 Block user comment: N Private report: N New Comment: We're definitely applying htmlspecialchars to errors in html_errors mode. Can you please double check that it is really enabled (e.g. by printing the html_errors ini setting in the same script you are testing the error message)? Previous Comments: ------------------------------------------------------------------------ [2018-10-27 19:08:57] david at grudl dot com Description: ------------ Displaying error messages is vulnerable to XSS, although the 'html_errors' is enabled. Solution is to convert especial charactes < & in error message (ie to use htmlspecialchars) Test script: --------------- <?php echo ${'<script>alert(123);</script>'}; Expected result: ---------------- In web browser it should not pop up the alert window, but it should report: "Notice: Undefined variable: <script>alert(123);</script> in test.php on line 3 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=77074&edit=1