Possible Content Security Policy bypass in Action Dispatch

Vulnerability Description

Action Pack is a framework for handling and responding to web requests. There is a possible Cross Site Scripting (XSS) vulnerability in the `content_security_policy` helper starting in version 5.2.0 of Action Pack and prior to versions 7.0.8.7, 7.1.5.1, 7.2.2.1, and 8.0.0.1. Applications which set Content-Security-Policy (CSP) headers dynamically from untrusted user input may be vulnerable to carefully crafted inputs being able to inject new directives into the CSP. This could lead to a bypass of the CSP and its protection against XSS and other attacks. Versions 7.0.8.7, 7.1.5.1, 7.2.2.1, and 8.0.0.1 contain a fix. As a workaround, applications can avoid setting CSP headers dynamically from untrusted input, or can validate/sanitize that input.

References

• https://github.com/rails/rails/security/advisories/GHSA-vfm5-rmrh-j26v
• https://github.com/rails/rails/commit/2e3f41e4538b9ca1044357f6644f037bbb7c6c49
• https://github.com/rails/rails/commit/3da2479cfe1e00177114b17e496213c40d286b3a
• https://github.com/rails/rails/commit/5558e72f22fc69c1c407b31ac5fb3b4ce087b542
• https://github.com/rails/rails/commit/cb16a3bb515b5d769f73926d9757270ace691f1d