AAE-42904 Escape html in evaluated fields and variables for rich-text display widget (#11718)

lib/core/src/lib/form/components/widgets/base-display-text/base-display-text.widget.ts

@@ -68,8 +68,8 @@ export abstract class BaseDisplayTextWidgetComponent extends WidgetComponent imp
     protected abstract reevaluateExpressions(): void;
     private readonly destroyRef = inject(DestroyRef);
 
-    protected resolveExpressions(text: string): string {
-        return this.formExpressionService.resolveExpressions(this.field.form, text);
+    protected resolveExpressions(text: string, escapeHtml?: boolean): string {
+        return this.formExpressionService.resolveExpressions(this.field.form, text, escapeHtml);
     }
 
     private applyExpressions() {

lib/core/src/lib/form/services/form-expression.service.spec.ts

@@ -268,6 +268,34 @@ describe('FormExpressionService', () => {
 
             expect(result).toBe('true');
         });
+
+        describe('when escapeHtml is true', () => {
+            let getFieldSpy: jasmine.Spy;
+
+            beforeEach(() => {
+                getFieldSpy = spyOn(formModel, 'getFieldById');
+            });
+
+            it('should escape ampersands in resolved field values', () => {
+                getFieldSpy.and.returnValue({ id: 'f', value: 'a & b' } as any);
+                expect(service.resolveExpressions(formModel, '${field.f}', true)).toBe('a & b');
+            });
+
+            it('should escape all HTML special characters in an XSS-like payload', () => {
+                getFieldSpy.and.returnValue({ id: 'f', value: `<img src="x" onerror='alert(1)'>` } as any);
+                expect(service.resolveExpressions(formModel, '${field.f}', true)).toBe('&lt;img src=&quot;x&quot; onerror=&#039;alert(1)&#039;&gt;');
+            });
+
+            it('should not escape characters when escapeHtml is false', () => {
+                getFieldSpy.and.returnValue({ id: 'f', value: '<b>bold</b>' } as any);
+                expect(service.resolveExpressions(formModel, '${field.f}', false)).toBe('<b>bold</b>');
+            });
+
+            it('should not escape characters when escapeHtml is omitted', () => {
+                getFieldSpy.and.returnValue({ id: 'f', value: '<b>bold</b>' } as any);
+                expect(service.resolveExpressions(formModel, '${field.f}')).toBe('<b>bold</b>');
+            });
+        });
     });
 
     describe('getFieldDependencies', () => {

lib/core/src/lib/form/services/form-expression.service.ts

@@ -27,7 +27,7 @@ export class FormExpressionService {
     private readonly VARIABLE_PREFIX = 'variable.';
     private readonly VARIABLES_REGEX = /(?:field|variable)\.[a-zA-Z_$][a-zA-Z0-9_$]*/g;
 
-    resolveExpressions(form: FormModel, formField: string): string {
+    resolveExpressions(form: FormModel, formField: string, escapeHtml?: boolean): string {
         let result = formField || '';
 
         const matches = result.match(this.GLOBAL_EXPRESSION_REGEX);
@@ -43,6 +43,19 @@ export class FormExpressionService {
             } else if (typeof expressionResult !== 'string') {
                 expressionResult = JSON.stringify(expressionResult);
             }
+            if (escapeHtml) {
+                expressionResult = expressionResult
+                    .split('&')
+                    .join('&')
+                    .split('<')
+                    .join('&lt;')
+                    .split('>')
+                    .join('&gt;')
+                    .split('"')
+                    .join('&quot;')
+                    .split("'")
+                    .join('&#039;');
+            }
             result = result.replace(match, expressionResult);
         }