Ruby on Rails Improper Neutralization of Input During Web Page Generation (Cross-site Scripting) Vulnerability - CVE-2020-8264
In actionpack gem gt 6.0.0 a possible XSS vulnerability exists when an application is running in development mode allowing an attacker to send or embed (in another page) a specially crafted URL which can allow the attacker to execute JavaScript in the context of the local application. This vulnerability is in the Actionable Exceptions middleware.