fix: prevent XSS vulnerability among sanification

src/components/FilePreview/FilePreview.tsx

@@ -126,9 +126,7 @@ const FilePreview = ({
     if (isHtmlFile(file)) {
       let htmlContent = content;
       if (htmlContent.includes('<') || htmlContent.includes('"')) {
-        const div = document.createElement('div');
-        div.innerHTML = htmlContent;
-        htmlContent = div.textContent || div.innerText || htmlContent;
+        htmlContent = stripHTML(htmlContent) || htmlContent;
       }
       htmlContent = stripDocumentAttachmentTags(htmlContent);
       return htmlContent;

src/components/MediaWidget/MediaItemWidget.tsx

@@ -11,6 +11,7 @@ import React, {
 import { getResourceUrl } from '../../helpers/media';
 import {
   withLinksOpenInNewTab,
+  stripHTML,
   stripDocumentAttachmentTags,
   isAssetOnlyDocumentAttachment,
   getDocumentAttachmentAssetUrl,
@@ -433,9 +434,7 @@ export const RenderMediaItem = memo(function RenderMediaItem({
           htmlContent.includes('<document_attachment')
         ) {
           if (htmlContent.includes('&lt;') || htmlContent.includes('&quot;')) {
-            const div = document.createElement('div');
-            div.innerHTML = htmlContent;
-            htmlContent = div.textContent || div.innerText || htmlContent;
+            htmlContent = stripHTML(htmlContent) || htmlContent;
           }
           htmlContent = stripDocumentAttachmentTags(htmlContent);
         }

src/components/MediaWidget/MediaPreviewModal.tsx

@@ -274,9 +274,7 @@ export function MediaPreviewModal({
             // HTML document attachment: display HTML content in a code-like format
             let htmlContent = medium.content || '';
             if (htmlContent.includes('<') || htmlContent.includes('"')) {
-              const div = document.createElement('div');
-              div.innerHTML = htmlContent;
-              htmlContent = div.textContent || div.innerText || htmlContent;
+              htmlContent = stripHTML(htmlContent) || htmlContent;
             } else {
               htmlContent = stripDocumentAttachmentTags(htmlContent);
             }
@@ -296,9 +294,7 @@ export function MediaPreviewModal({
             // Other document attachments: render as plain text
             let displayContent = medium.content;
             if (displayContent.includes('<') || displayContent.includes('"')) {
-              const div = document.createElement('div');
-              div.innerHTML = displayContent;
-              displayContent = div.textContent || div.innerText || displayContent;
+              displayContent = stripHTML(displayContent) || displayContent;
             } else {
               displayContent = stripDocumentAttachmentTags(displayContent);
             }

src/helpers/message.test.ts

@@ -1,4 +1,24 @@
-import { renderMsg, stripAttachmentTags, stripAllInternalTags } from './message';
+import {
+  renderMsg,
+  sanitizeMsg,
+  stripAttachmentTags,
+  stripAllInternalTags,
+} from './message';
+
+describe('sanitizeMsg', () => {
+  it('strips onerror from partner XSS img payload', () => {
+    const payload =
+      '<img src="immagine-inesistente.jpg" onerror="alert(\'XSS Eseguito!\')">';
+    const result = sanitizeMsg(payload);
+    expect(result).toBe('<img src="immagine-inesistente.jpg">');
+    expect(result).not.toMatch(/onerror/i);
+  });
+
+  it('strips svg onload handlers', () => {
+    const result = sanitizeMsg('<svg onload="alert(1)"></svg>');
+    expect(result).not.toMatch(/onload/i);
+  });
+});
 
 describe('renderMsg', () => {
   it('should render message with reasoning and output tag adjacent correctly', () => {
@@ -11,6 +31,13 @@ describe('renderMsg', () => {
       '<details class="memori-think"><summary>Reasoning...</summary>L\'utente vuole che io elenchi i parametri dell\'ALBERO ESISTENTE.</details>\n\n<output class="rails-query" style="display:none">\nproject = Project.find("68d99b05783713e16737d32b")\n</output>\n\n<p>Recupero tutti i 7 parametri dell\'ALBERO ESISTENTE...</p>'
     );
   });
+
+  it('strips onerror from XSS img payload in rendered output', () => {
+    const payload =
+      '<img src="immagine-inesistente.jpg" onerror="alert(\'XSS Eseguito!\')">';
+    const result = renderMsg(payload, false, 'Reasoning...', false);
+    expect(result.text).not.toMatch(/onerror/i);
+  });
 });
 
 describe('stripAttachmentTags', () => {

src/helpers/message.ts

@@ -85,6 +85,9 @@ export const truncateMessage = (message: string) => {
   return truncatedMessage;
 };
 
+export const sanitizeMsg = (msg: string) =>
+  DOMPurify.sanitize(msg, { ADD_ATTR: ['target'] });
+
 export const renderMsg = (
   text: string,
   useMathFormatting = false,
@@ -196,9 +199,6 @@ export const renderMsg = (
     return { text: finalText };
   } catch (e) {
     console.error('Error rendering message:', e);
-    return { text };
+    return { text: sanitizeMsg(text) };
   }
 };
-
-export const sanitizeMsg = (msg: string) =>
-  DOMPurify.sanitize(msg, { ADD_ATTR: ['target'] });

src/helpers/utils.test.ts

@@ -1,6 +1,7 @@
 import {
   difference,
   stripEmojis,
+  stripHTML,
   stripMarkdown,
   stripOutputTags,
   escapeHTML,
@@ -254,6 +255,54 @@ describe('utils/attachment helpers', () => {
   });
 });
 
+describe('utils/stripHTML', () => {
+  it('strips tags and returns text content', () => {
+    expect(stripHTML('<p>Hello <strong>world</strong></p>')).toBe(
+      'Hello world'
+    );
+  });
+
+  it('does not retain onerror from partner XSS payload', () => {
+    const payload =
+      '<img src="immagine-inesistente.jpg" onerror="alert(\'XSS Eseguito!\')">';
+    const result = stripHTML(payload);
+    expect(result).toBe('');
+    expect(result).not.toMatch(/onerror/i);
+    // Re-parse result: must not introduce an executable handler attribute
+    const reparsed = new DOMParser().parseFromString(result, 'text/html');
+    expect(reparsed.querySelector('[onerror]')).toBeNull();
+    expect(reparsed.querySelector('img')).toBeNull();
+  });
+
+  it('strips svg onload payloads without leaving handlers', () => {
+    const payload = '<svg onload="alert(1)"><text>x</text></svg>';
+    const result = stripHTML(payload);
+    expect(result).toBe('x');
+    expect(result).not.toMatch(/onload/i);
+  });
+
+  it('decodes HTML entities without executing nested markup', () => {
+    const encoded =
+      '&lt;img src="x" onerror="alert(1)"&gt;hello&lt;/img&gt;';
+    const result = stripHTML(encoded);
+    expect(result).toContain('hello');
+    // Entity-decoded text may contain the string "onerror" as text; ensure no live element
+    const reparsed = new DOMParser().parseFromString(
+      `<div>${result.replace(/</g, '&lt;')}</div>`,
+      'text/html'
+    );
+    expect(reparsed.querySelector('[onerror]')).toBeNull();
+  });
+
+  it('handles nested tags', () => {
+    expect(stripHTML('<div><span>a</span><b>b</b></div>')).toBe('ab');
+  });
+
+  it('returns empty string for empty input', () => {
+    expect(stripHTML('')).toBe('');
+  });
+});
+
 describe('utils/parsing combined', () => {
   it('should remove output tag from real message', () => {
     const result = escapeHTML(

src/helpers/utils.ts

@@ -363,10 +363,23 @@ export const stripReasoningTags = (text: string) => {
   return strippedText;
 };
 
+/**
+ * Strip HTML tags / decode entities without executing scripts or event handlers.
+ * Uses an inert DOMParser document (no resource loads / onerror), unlike live innerHTML.
+ */
 export const stripHTML = (text: string) => {
-  const el = document.createElement('div');
-  el.innerHTML = text;
-  return el.textContent || '';
+  if (typeof DOMParser !== 'undefined') {
+    try {
+      return (
+        new DOMParser().parseFromString(text, 'text/html').body.textContent ||
+        ''
+      );
+    } catch {
+      // fall through
+    }
+  }
+  // Non-DOM / parse failure: strip tags only (does not decode entities)
+  return text.replace(/<[^>]*>/g, '');
 };
 
 /** Ensures all <a> tags in HTML open in a new tab (target="_blank" rel="noopener noreferrer"). */