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GHSA-mqq5-j7w8-2hgh
No affected components available
Unauthenticated nested page API leaks restricted & unpublished content
- Location:
app/controllers/alchemy/api/pages_controller.rb:28(Api::PagesController#nested) - Affected version: Alchemy CMS 8.3.0.dev (Rails 8.1.3)
Description
The unauthenticated GET /api/pages/nested endpoint returns the full page tree to any anonymous caller, including restricted (member-only) pages and unpublished/draft pages that should be hidden.
Appending ?elements=true additionally dumps the element/ingredient content of restricted pages, fully bypassing the access control the sibling show and index actions enforce.
Root cause
Api::PagesController#nested calls no authorize! and applies no published/restricted scoping, unlike show (authorize! :show) and index (accessible_by(current_ability, :index)).
PageTreePreloader loads page.self_and_descendants unfiltered, and PageTreeSerializer emits every page's metadata (and, with elements, public_version.elements) with no ability check.
Evidence
An unauthenticated GET /api/pages/nested returns HTTP 200 with the restricted page ("restricted":true) and an unpublished draft ("public":false); ?elements=true leaks its content (e.g. TOPSECRET_RESTRICTED_BODY_proof123).
The same guest hitting GET /api/pages/3 (show) gets HTTP 403 {"error":"Not authorized"}, proving nested returns what show correctly denies.
Reproduction
# 1) Metadata leak (guest, no auth)
curl -s http://localhost:3000/api/pages/nested | python3 -m json.tool | grep -E '"name"|"restricted"|"public"'
# 2) Content leak of restricted page
curl -s "http://localhost:3000/api/pages/nested?elements=true" | grep -oE 'TOPSECRET_RESTRICTED_BODY_[A-Za-z0-9]+|RESTRICTED_RICHTEXT_[A-Za-z0-9]+'
# 3) Contrast — show denies the same guest
curl -s -o /dev/null -w "show /api/pages/3 -> HTTP %{http_code}\n" http://localhost:3000/api/pages/3
Suggested fix
def nested
@page = Page.find_by(id: params[:page_id]) || Language.current_root_page
authorize! :show, @page
preloaded_page = PageTreePreloader.new(page: @page, user: current_alchemy_user, ability: current_ability).call
render json: PageTreeSerializer.new(preloaded_page, ability: current_ability,
user: current_alchemy_user, elements: params[:elements])
end
Additionally scope PageTreePreloader's self_and_descendants via accessible_by(current_ability) and gate element emission in PageTreeSerializer#page_elements behind opts[:ability].can?(:show, page).
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
Probability that this vulnerability will be exploited in the wild within the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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