Alchemy: Unauthenticated nested page API leaks restricted & unpublished content

Alchemy is an open source content management system engine written in Ruby on Rails. Prior to 7.4.15, 8.0.15, 8.1.14, and 8.2.6, the unauthenticated GET /api/pages/nested endpoint implemented by Api::PagesController#nested in app/controllers/alchemy/api/pages_controller.rb returns an unfiltered page tree because it performs no authorization and does not scope descendants by the caller's ability. Anonymous callers can retrieve restricted and unpublished page metadata that the sibling show action denies. When elements=true is supplied, PageTreeSerializer also returns element and ingredient content from restricted pages because PageTreePreloader and the serializer do not apply an ability check to those records. This issue is fixed in versions 7.4.15, 8.0.15, 8.1.14, and 8.2.6.

AlchemyCMS before 7.4.16 and 8.x before 8.3.6 Missing Authorization on GET /api/nodes

AlchemyCMS versions before 7.4.16 and 8.x before 8.3.6 fail to authorize access to the GET /api/nodes endpoint, allowing unauthenticated attackers to retrieve all navigation nodes. Attackers can access the endpoint without authentication to disclose restricted page names, URL paths, and internal URLs from all sites and languages.

AlchemyCMS has Authenticated Remote Code Execution (RCE) via eval injection in ResourcesHelper

Alchemy is an open source content management system engine written in Ruby on Rails. Prior to versions 7.4.12 and 8.0.3, the application uses the Ruby `eval()` function to dynamically execute a string provided by the `resource_handler.engine_name` attribute in `Alchemy::ResourcesHelper#resource_url_proxy`. The vulnerability exists in `app/helpers/alchemy/resources_helper.rb` at line 28. The code explicitly bypasses security linting with `# rubocop:disable Security/Eval`, indicating that the use of a dangerous function was known but not properly mitigated. Since `engine_name` is sourced from module definitions that can be influenced by administrative configurations, it allows an authenticated attacker to escape the Ruby sandbox and execute arbitrary system commands on the host OS. Versions 7.4.12 and 8.0.3 fix the issue by replacing `eval()` with `send()`.

A Stored XSS vulnerability has been discovered in version 4.1.0 of AlchemyCMS via the /admin/pictures image field. NOTE: the vendor's position is that this is not a valid report: "The researcher used an authorized cookie to perform the request to a password-protected route. Without that session cookie, the request would have been rejected as unauthorized."