Merge branch 'security-11-2-2717-fix-issue-title-xss' into 'security-11-2'

[11.2] Escape issue title while template rendering to prevent XSS

See merge request gitlab/gitlabhq!2558

3 files changed, 25 insertions, 4 deletions

diff --git a/app/assets/javascripts/gfm_auto_complete.js b/app/assets/javascripts/gfm_auto_complete.js
index 73b2cd0b2c7..03256ca2285 100644
--- a/app/assets/javascripts/gfm_auto_complete.js
+++ b/app/assets/javascripts/gfm_auto_complete.js
@@ -199,7 +199,7 @@ class GfmAutoComplete {
       displayTpl(value) {
         let tmpl = GfmAutoComplete.Loading.template;
         if (value.title != null) {
-          tmpl = GfmAutoComplete.Issues.template;
+          tmpl = GfmAutoComplete.Issues.templateFunction(value.id, value.title);
         }
         return tmpl;
       },
@@ -265,7 +265,7 @@ class GfmAutoComplete {
       displayTpl(value) {
         let tmpl = GfmAutoComplete.Loading.template;
         if (value.title != null) {
-          tmpl = GfmAutoComplete.Issues.template;
+          tmpl = GfmAutoComplete.Issues.templateFunction(value.id, value.title);
         }
         return tmpl;
       },
@@ -521,8 +521,9 @@ GfmAutoComplete.Labels = {
 };
 // Issues and MergeRequests
 GfmAutoComplete.Issues = {
-  // eslint-disable-next-line no-template-curly-in-string
-  template: '<li><small>${id}</small> ${title}</li>',
+  templateFunction(id, title) {
+    return `<li><small>${id}</small> ${_.escape(title)}</li>`;
+  },
 };
 // Milestones
 GfmAutoComplete.Milestones = {
diff --git a/changelogs/unreleased/security-11-2-2717-fix-issue-title-xss.yml b/changelogs/unreleased/security-11-2-2717-fix-issue-title-xss.yml
new file mode 100644
index 00000000000..346f31956f4
--- /dev/null
+++ b/changelogs/unreleased/security-11-2-2717-fix-issue-title-xss.yml
@@ -0,0 +1,5 @@
+---
+title: Escape entity title while autocomplete template rendering to prevent XSS
+merge_request: 2558
+author:
+type: security
diff --git a/spec/features/issues/gfm_autocomplete_spec.rb b/spec/features/issues/gfm_autocomplete_spec.rb
index 98e37d8011a..8a43847d64d 100644
--- a/spec/features/issues/gfm_autocomplete_spec.rb
+++ b/spec/features/issues/gfm_autocomplete_spec.rb
@@ -34,6 +34,21 @@ describe 'GFM autocomplete', :js do
     expect(page).to have_selector('.atwho-container')
   end
 
+  it 'opens autocomplete menu when field starts with text with item escaping HTML characters' do
+    alert_title = 'This will execute alert<img src=x onerror=alert(2)&lt;img src=x onerror=alert(1)&gt;'
+    create(:issue, project: project, title: alert_title)
+
+    page.within '.timeline-content-form' do
+      find('#note-body').native.send_keys('#')
+    end
+
+    expect(page).to have_selector('.atwho-container')
+
+    page.within '.atwho-container #at-view-issues' do
+      expect(page.all('li').first.text).to include(alert_title)
+    end
+  end
+
   it 'doesnt open autocomplete menu character is prefixed with text' do
     page.within '.timeline-content-form' do
       find('#note-body').native.send_keys('testing')