diff --git a/frontend/src/__tests__/apikeys.test.ts b/frontend/src/__tests__/apikeys.test.ts
index 978bdd30c..3cc12f54b 100644
--- a/frontend/src/__tests__/apikeys.test.ts
+++ b/frontend/src/__tests__/apikeys.test.ts
@@ -289,6 +289,33 @@ describe('API Keys Module', () => {
       expect(api.revokeApiKey).toHaveBeenCalledWith('key-1');
     });
 
+    // Regression for ARCH-07 (issue #1195): the previous local escapeHtml
+    // copy (div.textContent -> div.innerHTML round-trip) did not escape
+    // quote characters, so a key id containing a double quote interpolated
+    // into data-key-id="..." broke out of the attribute and injected a new
+    // attribute (here onmouseover) into the button markup.
+    test('issue #1195: double quote in key id cannot inject attributes', async () => {
+      const hostileId = 'key-1" onmouseover="alert(1)';
+      const mockKeys = [
+        {
+          id: hostileId,
+          name: 'Hostile Key',
+          key_prefix: 'abc123',
+          is_active: true,
+          created_at: '2024-01-15T10:00:00Z'
+        }
+      ];
+
+      (api.getApiKeys as jest.Mock).mockResolvedValue({ api_keys: mockKeys });
+
+      await loadApiKeys();
+
+      const deleteBtn = document.querySelector('.delete-key-btn');
+      expect(deleteBtn).not.toBeNull();
+      expect(deleteBtn?.getAttribute('onmouseover')).toBeNull();
+      expect(deleteBtn?.getAttribute('data-key-id')).toBe(hostileId);
+    });
+
     test('adds event listener to delete buttons', async () => {
       const mockKeys = [
         {
diff --git a/frontend/src/__tests__/users.test.ts b/frontend/src/__tests__/users.test.ts
index f623080fd..8fa65e3f5 100644
--- a/frontend/src/__tests__/users.test.ts
+++ b/frontend/src/__tests__/users.test.ts
@@ -122,7 +122,7 @@ describe('users/utils', () => {
   describe('escapeHtml', () => {
     it('should escape HTML special characters', () => {
       expect(userUtils.escapeHtml('<script>alert("xss")</script>')).toBe(
-        '&lt;script&gt;alert("xss")&lt;/script&gt;'
+        '&lt;script&gt;alert(&quot;xss&quot;)&lt;/script&gt;'
       );
     });
 
@@ -134,14 +134,28 @@ describe('users/utils', () => {
       expect(userUtils.escapeHtml('Tom & Jerry')).toBe('Tom &amp; Jerry');
     });
 
+    // Regression for ARCH-07 (issue #1195): the previous local DOM
+    // round-trip implementation left both quote characters unescaped,
+    // so values interpolated inside double-quoted attributes (e.g. the
+    // aria-label carrying the user email in userList.ts) could break
+    // out of the attribute and inject markup.
     it('should escape single quotes', () => {
       const result = userUtils.escapeHtml("It's a test");
-      expect(result).toBe("It's a test");
+      expect(result).toBe('It&#39;s a test');
     });
 
     it('should escape double quotes', () => {
       const result = userUtils.escapeHtml('Say "Hello"');
-      expect(result).toBe('Say "Hello"');
+      expect(result).toBe('Say &quot;Hello&quot;');
+    });
+
+    it('issue #1195: quote in attribute position cannot break out of the attribute', () => {
+      const malicious = 'a@b.com" onmouseover="alert(1)';
+      const div = document.createElement('div');
+      div.innerHTML = `<button aria-label="${userUtils.escapeHtml(malicious)}">x</button>`;
+      const btn = div.querySelector('button');
+      expect(btn?.getAttribute('onmouseover')).toBeNull();
+      expect(btn?.getAttribute('aria-label')).toBe(malicious);
     });
 
     it('should handle empty string', () => {
@@ -150,7 +164,7 @@ describe('users/utils', () => {
 
     it('should handle multiple special characters', () => {
       expect(userUtils.escapeHtml('<div class="test">&</div>')).toBe(
-        '&lt;div class="test"&gt;&amp;&lt;/div&gt;'
+        '&lt;div class=&quot;test&quot;&gt;&amp;&lt;/div&gt;'
       );
     });
   });
@@ -668,11 +682,15 @@ describe('users/filters', () => {
       userFilters.updateGroupFilterDropdown();
 
       const select = document.getElementById('user-group-filter') as HTMLSelectElement;
+      // No element may be injected out of the value attribute.
+      expect(select.querySelector('img')).toBeNull();
       // The raw payload must not appear verbatim inside the rendered HTML.
       expect(select.innerHTML).not.toContain('"><img src=x');
-      // The option's value should be the escaped form.
+      // With full escaping (issue #1195 made escapeHtml quote-safe), the
+      // option value round-trips the original id intact instead of being
+      // truncated at the first double quote.
       const opt = select.options[1];
-      expect(opt?.value).not.toContain('<img');
+      expect(opt?.value).toBe('"><img src=x onerror=alert(1)>');
     });
   });
 });
diff --git a/frontend/src/apikeys.ts b/frontend/src/apikeys.ts
index fb4633be8..ee358e9b7 100644
--- a/frontend/src/apikeys.ts
+++ b/frontend/src/apikeys.ts
@@ -4,7 +4,7 @@
 
 import * as api from './api';
 import type { APIKeyInfo, CreateAPIKeyResponse } from './types';
-import { formatDateTime, formatRelativeTime } from './utils';
+import { escapeHtml, formatDateTime, formatRelativeTime } from './utils';
 import { confirmDialog } from './confirmDialog';
 import { showToast } from './toast';
 import { openModal, closeModal } from './modal';
@@ -389,12 +389,3 @@ function showError(message: string): void {
     showToast({ message, kind: 'error' });
   }
 }
-
-/**
- * Escape HTML to prevent XSS
- */
-function escapeHtml(text: string): string {
-  const div = document.createElement('div');
-  div.textContent = text;
-  return div.innerHTML;
-}
diff --git a/frontend/src/users/utils.ts b/frontend/src/users/utils.ts
index afee4627d..0e78640b8 100644
--- a/frontend/src/users/utils.ts
+++ b/frontend/src/users/utils.ts
@@ -10,13 +10,14 @@
 export { formatRelativeTime, formatDate } from '../utils';
 
 /**
- * Escape HTML to prevent XSS
+ * Escape HTML to prevent XSS. Re-exported from the shared utils module:
+ * the previous local DOM round-trip (div.textContent -> div.innerHTML)
+ * did not escape quote characters, so values interpolated inside
+ * double-quoted attributes could break out of the attribute. The shared
+ * implementation escapes &, <, >, " and ' and is safe in both text and
+ * attribute contexts.
  */
-export function escapeHtml(text: string): string {
-  const div = document.createElement('div');
-  div.textContent = text;
-  return div.innerHTML;
-}
+export { escapeHtml } from '../utils';
 
 import { showToast } from '../toast';