Resolve: Guest can set weight of a new issue

Delete weight parameter when guest is creating issuables.

ee/app/services/ee/issuable_base_service.rb

@@ -3,7 +3,13 @@ module EE
     private
 
     def filter_params(issuable)
-      params.delete(:weight) unless issuable.supports_weight?
+      # This security check is repeated here to avoid multiple backports,
+      # this should be refactored to be reused from the base class.
+      ability_name = :"admin_#{issuable.to_ability_name}"
+
+      unless issuable.supports_weight? && can?(current_user, ability_name, issuable)
+        params.delete(:weight)
+      end
 
       super
     end

ee/changelogs/unreleased/security-issue_7696.yml

+---
+title: 'Resolve: Guest can set weight of a new issue'
+merge_request:
+author:
+type: security

ee/spec/services/issues/create_service_spec.rb

+require 'spec_helper'
+
+describe Issues::CreateService do
+  let(:project) { create(:project) }
+
+  let(:opts) do
+    {
+      title: 'Awesome issue',
+      description: 'please fix',
+      weight: 9
+    }
+  end
+
+  context 'when current user cannot admin issues in the project' do
+    let(:guest) { create(:user) }
+
+    before do
+      project.add_guest(guest)
+    end
+
+    it 'filters out params that cannot be set without the :admin_issue permission' do
+      issue = described_class.new(project, guest, opts).execute
+
+      expect(issue).to be_persisted
+      expect(issue.weight).to be_nil
+    end
+  end
+
+  context 'when current user can admin issues in the project' do
+    let(:reporter) { create(:user) }
+
+    before do
+      project.add_reporter(reporter)
+    end
+
+    it 'sets permitted params correctly' do
+      issue = described_class.new(project, reporter, opts).execute
+
+      expect(issue).to be_persisted
+      expect(issue.weight).to eq(9)
+    end
+  end
+end