GHSA-jvqq-cvh4-xm37: Decidim: Admin user search allows SQL injection through similarity-based sorting

The admin organization user search uses the untrusted term value inside raw SQL ORDER BY expressions. Because the value is interpolated before Rails sanitization is applied, a crafted search string is executed by PostgreSQL as part of the sort expression. Technical description The vulnerable endpoint is exposed as GET /admin/organization/users in decidim-admin/config/routes.rb: resource :organization, only: [:edit, :update], controller: "organization" do member do get :users end end That route reaches Decidim::Admin::OrganizationController#users, which forwards the current organization's available users into search: def users search(current_organization.users.available) end Inside search, the attacker-controlled source is params[:term]: if (term = params[:term].to_s).present? The query has two branches. In both branches, the WHERE predicates use bind parameters and are not the injection sink. The vulnerability is in the subsequent .order(Arel.sql(...)) calls, where the untrusted value is interpolated directly into SQL string literals. Nickname branch: nickname = term.delete("@") relation.where("nickname LIKE ?", "#{nickname}%") .order(Arel.sql(ActiveRecord::Base.sanitize_sql_array("similarity(nickname, '#{nickname}') DESC"))) Name/email branch: relation.where("name ILIKE ?", "%#{term}%").or( relation.where("email ILIKE ?", "%#{term}%") ) .order(Arel.sql(ActiveRecord::Base.sanitize_sql_array("GREATEST(similarity(name, '#{term}'), similarity(email, '#{term}')) DESC"))) .order(Arel.sql(ActiveRecord::Base.sanitize_sql_array("(similarity(name, '#{term}') + similarity(email, '#{term}')) / 2 DESC"))) This use of sanitize_sql_array does not make the code safe. The interpolation happens first, so Rails receives an already-built SQL string rather than a statement with bind placeholders. As a result, a quote in term can terminate the intended string literal and inject attacker-controlled SQL into the ORDER BY expression. For example, a payload such as slpleak '),