Symfony Cross-site Scripting

In Symfony before 2.7.51, 2.8.x before 2.8.50, 3.x before 3.4.26, 4.x before 4.1.12, and 4.2.x before 4.2.7, HTTP Methods provided as verbs or using the override header may be treated as trusted input, but they are not validated, possibly causing SQL injection or XSS. This is related to symfony/http-foundation. (2019-05-16, CVE-2019-10913)

In Symfony before 2.7.51, 2.8.x before 2.8.50, 3.x before 3.4.26, 4.x before 4.1.12, and 4.2.x before 4.2.7, validation messages are not escaped, which can lead to XSS when user input is included. This is related to symfony/framework-bundle. (2019-05-16, CVE-2019-10909)

** DISPUTED ** Reflected Cross-site scripting (XSS) vulnerability in the web profiler in SensioLabs Symfony 3.3.6 allows remote attackers to inject arbitrary web script or HTML via the "file" parameter, aka an _profiler/open?file= URI. NOTE: The vendor states "The XSS ... is in the web profiler, a tool that should never be deployed in production (so, we don't handle those issues as security issues)." (2018-06-13, CVE-2018-12040)

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>