diff --git a/packages/quill/package.json b/packages/quill/package.json
index 6f2598e512..6014a9af9f 100644
--- a/packages/quill/package.json
+++ b/packages/quill/package.json
@@ -1,6 +1,6 @@
 {
   "name": "quill",
-  "version": "2.0.3",
+  "version": "1.3.7-snyk-fix.1",
   "description": "Your powerful, rich text editor",
   "author": "Jason Chen <jhchen7@gmail.com>",
   "homepage": "https://quilljs.com",
diff --git a/packages/quill/src/blots/break.ts b/packages/quill/src/blots/break.ts
index db4c2a7faf..9b196aa098 100644
--- a/packages/quill/src/blots/break.ts
+++ b/packages/quill/src/blots/break.ts
@@ -18,6 +18,10 @@ class Break extends EmbedBlot {
   value() {
     return '';
   }
+
+  html() {
+    return '<br>';
+  }
 }
 Break.blotName = 'break';
 Break.tagName = 'BR';
diff --git a/packages/quill/src/core/editor.ts b/packages/quill/src/core/editor.ts
index b6391a7cd4..bbbfc8c665 100644
--- a/packages/quill/src/core/editor.ts
+++ b/packages/quill/src/core/editor.ts
@@ -7,6 +7,10 @@ import Break from '../blots/break.js';
 import CursorBlot from '../blots/cursor.js';
 import type Scroll from '../blots/scroll.js';
 import TextBlot, { escapeText } from '../blots/text.js';
+import {
+  cloneWithSafeAttributes,
+  getSafeWrapperMarkup,
+} from './html_escape.js';
 import { Range } from './selection.js';
 
 const ASCII = /^[ -~]*$/;
@@ -399,15 +403,20 @@ function convertHTML(
     if (isRoot || blot.statics.blotName === 'list') {
       return parts.join('');
     }
-    const { outerHTML, innerHTML } = blot.domNode as Element;
-    const [start, end] = outerHTML.split(`>${innerHTML}<`);
-    // TODO cleanup
-    if (start === '<table') {
-      return `<table style="border: 1px solid #000;">${parts.join('')}<${end}`;
+    const domNode = blot.domNode as Element;
+    const [start, end] = getSafeWrapperMarkup(domNode);
+    if (domNode.tagName === 'TABLE') {
+      return `<table style="border: 1px solid #000;">${parts.join('')}${end}`;
     }
-    return `${start}>${parts.join('')}<${end}`;
+    if (end === '') {
+      return `${start}${parts.join('')}`;
+    }
+    return `${start}${parts.join('')}${end}`;
+  }
+  if (blot.domNode instanceof Element) {
+    return cloneWithSafeAttributes(blot.domNode).outerHTML;
   }
-  return blot.domNode instanceof Element ? blot.domNode.outerHTML : '';
+  return '';
 }
 
 function combineFormats(
diff --git a/packages/quill/src/core/html_escape.ts b/packages/quill/src/core/html_escape.ts
new file mode 100644
index 0000000000..b20f2a1987
--- /dev/null
+++ b/packages/quill/src/core/html_escape.ts
@@ -0,0 +1,76 @@
+import { escapeText } from '../blots/text.js';
+
+/** HTML body / text node context (same as TextBlot escape). */
+export const escapeHtml = escapeText;
+
+/** Double-quoted attribute context. */
+export function escapeAttribute(value: string): string {
+  return value.replace(/[&<>"'\n\r\t]/g, (ch) => {
+    switch (ch) {
+      case '&':
+        return '&amp;';
+      case '<':
+        return '&lt;';
+      case '>':
+        return '&gt;';
+      case '"':
+        return '&quot;';
+      case "'":
+        return '&#39;';
+      case '\n':
+        return '&#10;';
+      case '\r':
+        return '&#13;';
+      case '\t':
+        return '&#9;';
+      default:
+        return ch;
+    }
+  });
+}
+
+export function stripDangerousAttributes(element: Element): void {
+  for (const attr of Array.from(element.attributes)) {
+    const name = attr.name.toLowerCase();
+    if (name.startsWith('on')) {
+      element.removeAttribute(attr.name);
+      continue;
+    }
+    const val = attr.value;
+    if (
+      (name === 'href' || name === 'src' || name === 'xlink:href') &&
+      /^\s*javascript:/i.test(val)
+    ) {
+      element.removeAttribute(attr.name);
+    }
+  }
+}
+
+const EXPORT_MARKER = '\uE000QUILL_HTML_EXPORT\uE000';
+
+/**
+ * Safe open/close fragments for a non-void element by cloning the shell,
+ * stripping dangerous attributes, and replacing inner HTML with a marker.
+ */
+export function getSafeWrapperMarkup(domNode: Element): [string, string] {
+  const shell = domNode.cloneNode(false) as Element;
+  stripDangerousAttributes(shell);
+  shell.innerHTML = EXPORT_MARKER;
+  const outer = shell.outerHTML;
+  const idx = outer.indexOf(EXPORT_MARKER);
+  if (idx === -1) {
+    return [shell.outerHTML, ''];
+  }
+  return [outer.slice(0, idx), outer.slice(idx + EXPORT_MARKER.length)];
+}
+
+/** Clone subtree and strip event handlers / javascript: URLs from every element. */
+export function cloneWithSafeAttributes(root: Element): Element {
+  const clone = root.cloneNode(true) as Element;
+  const walk = (el: Element) => {
+    stripDangerousAttributes(el);
+    Array.from(el.children).forEach((ch) => walk(ch));
+  };
+  walk(clone);
+  return clone;
+}
diff --git a/packages/quill/src/formats/formula.ts b/packages/quill/src/formats/formula.ts
index ded4e89160..5c303aa8b9 100644
--- a/packages/quill/src/formats/formula.ts
+++ b/packages/quill/src/formats/formula.ts
@@ -1,4 +1,5 @@
 import Embed from '../blots/embed.js';
+import { escapeHtml } from '../core/html_escape.js';
 
 class Formula extends Embed {
   static blotName = 'formula';
@@ -27,8 +28,12 @@ class Formula extends Embed {
   }
 
   html() {
-    const { formula } = this.value();
-    return `<span>${formula}</span>`;
+    const dom = this.domNode as Element;
+    const raw =
+      (typeof this.value() === 'string' ? this.value() : null) ??
+      dom.getAttribute('data-value') ??
+      '';
+    return `<span class="ql-formula">${escapeHtml(raw)}</span>`;
   }
 }
 
diff --git a/packages/quill/src/formats/image.ts b/packages/quill/src/formats/image.ts
index e68f56a0b3..5e311bb632 100644
--- a/packages/quill/src/formats/image.ts
+++ b/packages/quill/src/formats/image.ts
@@ -1,4 +1,5 @@
 import { EmbedBlot } from 'parchment';
+import { escapeAttribute } from '../core/html_escape.js';
 import { sanitize } from './link.js';
 
 const ATTRIBUTES = ['alt', 'height', 'width'];
@@ -52,6 +53,17 @@ class Image extends EmbedBlot {
       super.format(name, value);
     }
   }
+
+  html() {
+    const src = Image.sanitize(this.domNode.getAttribute('src') || '');
+    const formats = Image.formats(this.domNode);
+    const parts = [`src="${escapeAttribute(src)}"`];
+    ATTRIBUTES.forEach((name) => {
+      const v = formats[name];
+      if (v) parts.push(`${name}="${escapeAttribute(v)}"`);
+    });
+    return `<img ${parts.join(' ')}>`;
+  }
 }
 
 export default Image;
diff --git a/packages/quill/src/formats/video.ts b/packages/quill/src/formats/video.ts
index 84d4bb15cf..f21f505320 100644
--- a/packages/quill/src/formats/video.ts
+++ b/packages/quill/src/formats/video.ts
@@ -1,4 +1,5 @@
 import { BlockEmbed } from '../blots/block.js';
+import { escapeAttribute, escapeHtml } from '../core/html_escape.js';
 import Link from './link.js';
 
 const ATTRIBUTES = ['height', 'width'];
@@ -51,8 +52,9 @@ class Video extends BlockEmbed {
   }
 
   html() {
-    const { video } = this.value();
-    return `<a href="${video}">${video}</a>`;
+    const raw = this.domNode.getAttribute('src') ?? '';
+    const safe = Video.sanitize(raw);
+    return `<a href="${escapeAttribute(safe)}">${escapeHtml(safe)}</a>`;
   }
 }
 
diff --git a/packages/quill/src/modules/syntax.ts b/packages/quill/src/modules/syntax.ts
index da99fdc41d..685bb5eb0c 100644
--- a/packages/quill/src/modules/syntax.ts
+++ b/packages/quill/src/modules/syntax.ts
@@ -3,6 +3,7 @@ import { ClassAttributor, Scope } from 'parchment';
 import type { Blot, ScrollBlot } from 'parchment';
 import Inline from '../blots/inline.js';
 import Quill from '../core/quill.js';
+import { escapeAttribute } from '../core/html_escape.js';
 import Module from '../core/module.js';
 import { blockDelta } from '../blots/block.js';
 import BreakBlot from '../blots/break.js';
@@ -159,7 +160,7 @@ class SyntaxCodeBlockContainer extends CodeBlockContainer {
       ? SyntaxCodeBlock.formats(codeBlock.domNode)
       : 'plain';
 
-    return `<pre data-language="${language}">\n${escapeText(
+    return `<pre data-language="${escapeAttribute(language)}">\n${escapeText(
       this.code(index, length),
     )}\n</pre>`;
   }
diff --git a/packages/quill/test/unit/core/editor.spec.ts b/packages/quill/test/unit/core/editor.spec.ts
index 2d47a1dec9..3fcbedfd0e 100644
--- a/packages/quill/test/unit/core/editor.spec.ts
+++ b/packages/quill/test/unit/core/editor.spec.ts
@@ -25,6 +25,7 @@ import { SizeClass } from '../../../src/formats/size.js';
 import Blockquote from '../../../src/formats/blockquote.js';
 import IndentClass from '../../../src/formats/indent.js';
 import { ColorClass } from '../../../src/formats/color.js';
+import Formula from '../../../src/formats/formula.js';
 import Quill from '../../../src/core.js';
 import { normalizeHTML } from '../__helpers__/utils.js';
 
@@ -1409,5 +1410,76 @@ describe('Editor', () => {
       expect(editor.getHTML(2, 7)).toEqual('<pre>\n123\n\n\n4\n</pre>');
       expect(editor.getHTML(5, 7)).toEqual('<pre>\n\n\n\n4567\n</pre>');
     });
+
+    test('video html export escapes href and text for XSS payloads (CVE-2025-15056)', () => {
+      const editor = createEditor(
+        new Delta().insert({ video: 'https://example.test/' }).insert('\n'),
+      );
+      const iframe = editor.scroll.domNode.querySelector(
+        'iframe.ql-video',
+      ) as HTMLIFrameElement;
+      iframe.setAttribute(
+        'src',
+        'https://example.test/path?x=" onmouseover="alert(1)',
+      );
+      const html = editor.getHTML(0, editor.scroll.length() - 1);
+      expect(html).not.toMatch(/onmouseover/i);
+      expect(html).toContain('&quot;');
+    });
+
+    test('formula html export escapes injected markup (CVE-2025-15056)', () => {
+      const prevKatex = (window as unknown as { katex?: unknown }).katex;
+      (window as unknown as { katex: { render: () => void } }).katex = {
+        render: () => {},
+      };
+      const container = document.createElement('div');
+      document.body.appendChild(container);
+      const quill = new Quill(container, {
+        registry: createRegistry([
+          ListContainer,
+          List,
+          IndentClass,
+          Bold,
+          Image,
+          ColorClass,
+          Link,
+          FontClass,
+          Header,
+          Italic,
+          AlignClass,
+          Video,
+          Strike,
+          Underline,
+          CodeBlock,
+          CodeBlockContainer,
+          Blockquote,
+          SizeClass,
+          Formula,
+        ]),
+      });
+      quill.setContents(
+        new Delta()
+          .insert({ formula: '</span><img src=x onerror=alert(1)>' })
+          .insert('\n'),
+      );
+      const html = quill.editor.getHTML(0, quill.getLength() - 1);
+      expect(html).not.toMatch(/<img/i);
+      expect(html).toContain('&lt;/span&gt;');
+      if (prevKatex !== undefined) {
+        (window as unknown as { katex: unknown }).katex = prevKatex;
+      } else {
+        delete (window as unknown as { katex?: unknown }).katex;
+      }
+      quill.container.remove();
+    });
+
+    test('getHTML strips event attributes from blockquote wrapper', () => {
+      const editor = createEditor(
+        '<blockquote onmouseover="alert(1)">Quill</blockquote>',
+      );
+      const html = editor.getHTML(0, 6);
+      expect(html).not.toMatch(/onmouseover/i);
+      expect(html).toContain('Quill');
+    });
   });
 });
diff --git a/packages/quill/test/unit/vitest.config.ts b/packages/quill/test/unit/vitest.config.ts
index b279a46078..fdc7e26e1b 100644
--- a/packages/quill/test/unit/vitest.config.ts
+++ b/packages/quill/test/unit/vitest.config.ts
@@ -6,10 +6,10 @@ export default defineConfig({
     extensions: ['.ts', '.js'],
   },
   test: {
-    include: [resolve(__dirname, '**/*.spec.ts')],
+    include: ['test/unit/**/*.spec.ts'],
     typecheck: {
       enabled: true,
-      include: [resolve(__dirname, '**/*.test-d.ts')],
+      include: ['test/unit/**/*.test-d.ts'],
     },
     setupFiles: [
       resolve(__dirname, '__helpers__/expect.ts'),