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GHSA-6rf4-v2fh-m6p4

CriticalCVSS 10 / 10
Published Sep 24, 2026·Last modified Sep 24, 2026
Affected Components(1)
npm logosuneditor
< 2.47.11
Description

Summary

SUNEDITOR v2.47.10 appears to allow JavaScript execution through crafted namespaced HTML elements.

The sanitization logic does not fully remove executable event-handler attributes from certain custom/namespaced tags. As a result, an attacker may be able to inject HTML content that executes JavaScript when the rendered element is interacted with.

This behavior was observed after the changes introduced in this commit:

https://github.com/JiHong88/suneditor/commit/9ed405fb0de676e56cd0e6a13c19c103ad5948d3


Affected Version

Confirmed vulnerable:

  • SUNEDITOR =< 2.47.10

Potentially affected:

  • Previous versions, if the same sanitization logic is still present

Proof of Concept

The following payload preserves an executable event handler:

<a:b src="/x"><iframe src=javascript:alert(1)></iframe></a:b>

<p><a:b src="/x" onclick="document.body.style.background='red'">click</a:b></p>

Simplified PoC:

<a:b src="/x" onclick="console.log('XSS:',document.domain,document.cookie)">click</a:b>
<p><a:b src="/x" onmouseover="alert('XSS — '+document.domain)">📎 Click here for solutions</a:b></p>

Steps to Reproduce

  1. Open SUNEDITOR using version 2.47.10.
  2. Insert the payload above into the editor.
  3. Save or render the generated content.
  4. Click the generated element.
  5. Observe that JavaScript is executed.

Impact

This may allow an attacker to inject arbitrary JavaScript into rendered editor content.

Depending on how SUNEDITOR is integrated into an application, this could lead to:

  • Stored XSS
  • DOM manipulation
  • Session theft
  • Credential theft
  • Account takeover actions performed in the victim’s browser context

Technical Details

The issue appears to be related to incomplete handling of namespaced/custom HTML elements such as:

<a:b>

Event-handler attributes such as onclick can remain attached to these crafted elements and execute when interacted with.

This suggests that the sanitization process may not consistently normalize and validate custom or namespaced elements before applying attribute filtering.


Suggested Remediation

Possible mitigations include:

  • Normalize DOM elements before sanitization.
  • Explicitly reject or unwrap unknown/custom/namespaced tags.
  • Strip all event-handler attributes from all elements, including unknown/custom elements.
  • Re-validate sanitized output after browser DOM parsing.
  • Add regression tests for namespaced/custom tag payloads.

Upload your SBOM

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Risk Scores
Base Score
10.0

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
9.1

Active exploitation in the wild has been confirmed. Immediate patching or mitigation is required.

EPSS
0.39%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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