CVE-2026-57579

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 Anonymous callers can retrieve restricted and unpublished page metadata that the sibling show action denies.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.

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 Anonymous callers can retrieve restricted and unpublished page metadata that the sibling show action denies.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.

Unauthenticated nested page API leaks restricted & unpublished content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endpoint returns the full page tree to any anonymous caller, including restricted (member-only) pages and unpublished/draft pages that should be hidden.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).

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.

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.

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).