This article is a part of our Vulnerability Database (back to index)
Cross-site Scripting occurrences in Php
The Apache2 component in PHP before 5.6.38, 7.0.x before 7.0.32, 7.1.x before 7.1.22, and 7.2.x before 7.2.10 allows XSS via the body of a "Transfer-Encoding: chunked" request, because the bucket brigade is mishandled in the php_handler function in sapi/apache2handler/sapi_apache2.c. (2018-09-16, CVE-2018-17082)
An issue was discovered in ext/phar/phar_object.c in PHP before 5.6.36, 7.0.x before 7.0.30, 7.1.x before 7.1.17, and 7.2.x before 7.2.5. There is Reflected XSS on the PHAR 403 and 404 error pages via request data of a request for a .phar file. NOTE: this vulnerability exists because of an incomplete fix for CVE-2018-5712. (2018-04-29, CVE-2018-10547)
An issue was discovered in PHP before 5.6.33, 7.0.x before 7.0.27, 7.1.x before 7.1.13, and 7.2.x before 7.2.1. There is Reflected XSS on the PHAR 404 error page via the URI of a request for a .phar file. (2018-01-16, CVE-2018-5712)
Why Cross-site Scripting can be dangerous
Cross site scripting is an attack where a web page executes code that is injected by an adversary. It usually appears, when users input is presented. This attack can be used to impersonate a user, take over control of the session, or even steal API keys.
The attack can be executed e.g. when you application injects the request parameter directly into the HTML code of the page returned to the user:
https://server.com/confirmation?message=Transaction+Complete
what results in:
<span>Confirmation: Transaction Complete</span>
In that case the message can be modified to become a valid Javascript code, e.g.:
https://server.com/confirmation?message=<script>dangerous javascript code here</script>
and it will be executed locally by the user's browser with full access to the user's personal application/browser data:
<span>Confirmation: <script>dangerous javascript code here</script></span>