CVE-2026-59167: SunEditor XSS vulnerability in sanitizer with namespaced tags

CVE-2026-59167 · Severity: critical · CVSS 10 · Published 2026-09-23

SunEditor is a popular rich-text editor library used in web applications to allow users to create and edit formatted content. A critical vulnerability allows attackers to inject malicious JavaScript code through specially crafted HTML with namespaced tags, bypassing the editor's built-in sanitization. When a victim interacts with the injected element, the hidden JavaScript executes in their browser, enabling attackers to steal credentials, hijack sessions, or perform actions on the victim's behalf.

Vendors: npm.

Quick answers

Is CVE-2026-59167 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-59167 being exploited in the wild.
How severe is CVE-2026-59167?
Critical severity, with a CVSS score of 10, published 23 September 2026.
Which products and versions are affected?
suneditor (npm) <= 2.47.10, SEMVER:introduced=0,fixed=2.47.11.
Is there a fix for CVE-2026-59167?
Yes. suneditor (npm): upgrade to 2.47.11 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-59167 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-59167?
Check whether you run suneditor (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • suneditor (npm): upgrade to 2.47.11 or later
    npm install suneditor@2.47.11

Technical details

The vulnerability is an XSS (Cross-Site Scripting) vulnerability caused by incomplete sanitization of custom/namespaced HTML elements (e.g., &lt;a:b&gt;). The sanitizer fails to properly strip event-handler attributes (onclick, onmouseover, etc.) from these non-standard tags, leaving executable JavaScript intact. The flaw was introduced in a recent commit that changed the sanitization logic. The attack requires no authentication and is trivial to exploit—an attacker simply needs to inject the malicious payload into the editor content, which will execute when a user interacts with the rendered element. A patch should normalize all elements before sanitization and explicitly handle custom/namespaced tags.

Affected products

  • SunEditor SunEditor <=2.47.10

Identifiers

  • CVE-2026-59167
  • GHSA-6rf4-v2fh-m6p4

Timeline

  • 2026-09-24: disclosed

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.