Open Redirect in open-forms

Vulnerability Description

Open Forms is an application for creating and publishing smart forms. Prior to versions 1.0.9 and 1.1.1, the cookie consent page in Open Forms contains an open redirect by injecting a `referer` querystring parameter and failing to validate the value. A malicious actor is able to redirect users to a website under their control, opening them up for phishing attacks. The redirect is initiated by the open forms backend which is a legimate page, making it less obvious to end users they are being redirected to a malicious website. Versions 1.0.9 and 1.1.1 contain patches for this issue. There are no known workarounds avaialble.

References

• https://github.com/open-formulieren/open-forms/security/advisories/GHSA-c97h-m5qf-j8mf
• https://github.com/open-formulieren/open-forms/commit/3e8c9cce386e548765783354694fbb9d7a6ea7d3