CVE-2026-59167: SunEditor Critical XSS Vulnerability - Sanitizer Bypass
Summary
CVE-2026-59167: SunEditor: Critical XSS vulnerability - sanitizer bypass. Affects suneditor versions < 2.47.11. Fixed in 2.47.11. How to fix ↓
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Background
SunEditor is a lightweight and flexible WYSIWYG text editor designed for web applications. It allows users to create and edit rich text content easily. The editor supports various features such as image uploads, custom styling, and HTML content manipulation. However, a critical vulnerability has been identified in version 2.47.10, which allows attackers to execute JavaScript through crafted namespaced HTML elements due to inadequate sanitization.
Vulnerability Detail
The vulnerability arises from SunEditor's sanitization logic, which fails to completely remove executable event-handler attributes from certain custom or namespaced HTML tags. This flaw enables attackers to inject malicious HTML content that can execute JavaScript when the affected elements are interacted with. The issue was introduced in a specific commit, leading to potential risks such as stored XSS, DOM manipulation, session theft, credential theft, and account takeover actions performed in the victim's browser context.
How To Fix
Latest published version: 3.3.3 as of 22 Oct 2026
npm install suneditor@3.3.3Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
2.47.11
This is the first release that contains the fix.
npm install suneditor@2.47.11Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, you can normalize DOM elements before sanitization and explicitly reject or unwrap unknown/custom/namespaced tags. Additionally, consider stripping all event-handler attributes from all elements, including unknown/custom elements.
Conclusion
In summary, the critical XSS vulnerability identified as CVE-2026-59167 in SunEditor allows for JavaScript execution through crafted HTML elements due to inadequate sanitization. Users are strongly advised to update to the patched version 2.47.11 to mitigate this risk. Temporary workarounds can also be implemented to enhance security until an update can be performed.
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FAQ
The CVSS score of this vulnerability is 10.0, indicating a critical level of severity.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in real-time. Without requiring access to the code or installation, you can check your application using the package-lock.json file.
The vulnerability can lead to various impacts including stored XSS, DOM manipulation, session theft, credential theft, and account takeover actions performed in the victim's browser context.
Yes, you can implement workarounds such as normalizing DOM elements and stripping event-handler attributes from custom tags to reduce the risk until you can update.
More information can be found in the official GitHub advisory and the commit history that introduced the vulnerability.
References
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