SunEditor: Critical XSS vulnerability - sanitizer bypass

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

SunEditor is a lightweight and powerful WYSIWYG editor in vanilla JavaScript with no dependencies. Prior to 2.47.11, the sanitizer in src/lib/core.js does not consistently reject namespaced or custom HTML elements, allowing event-handler attributes to remain on crafted elements. When an application renders attacker-controlled editor content and a user interacts with the element, the retained handler can execute script in the application's browser origin, enabling stored cross-site scripting, data exposure, or unauthorized browser-context actions. This issue is fixed in version 2.47.11.

Source published

23 Sep 2026 13:52:56 UTC

Source modified

24 Sep 2026 14:52:33 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

SunEditor is a lightweight and powerful WYSIWYG editor in vanilla JavaScript with no dependencies. Prior to 2.47.11, the sanitizer in src/lib/core.js does not consistently reject namespaced or custom HTML elements, allowing event-handler attributes to remain on crafted elements. When an application renders attacker-controlled editor content and a user interacts with the element, the retained handler can execute script in the application's browser origin, enabling stored cross-site scripting, data exposure, or unauthorized browser-context actions. This issue is fixed in version 2.47.11.

Source published

Sep 23, 2026, 1:52:56 PM (timezone not stated)

Source modified

Sep 24, 2026, 2:52:33 PM (timezone not stated)

Observed here

11 Nov 2026 15:01:03 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

SunEditor is a lightweight and powerful WYSIWYG editor in vanilla JavaScript with no dependencies. Prior to 2.47.11, the sanitizer in src/lib/core.js does not consistently reject namespaced or custom HTML elements, allowing event-handler attributes to remain on crafted elements. When an application renders attacker-controlled editor content and a user interacts with the element, the retained handler can execute script in the application's browser origin, enabling stored cross-site scripting, data exposure, or unauthorized browser-context actions. This issue is fixed in version 2.47.11.

Source published

23 Sep 2026 14:17:07 UTC

Source modified

24 Sep 2026 15:17:25 UTC

Observed here

25 Oct 2026 14:19:16 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

## 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: ```html <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: ```html <a:b src="/x" onclick="console.log('XSS:',document.domain,document.cookie)">click</a:b> ``` ```html <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: ```html <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. ---

Source published

24 Sep 2026 14:57:55 UTC

Source modified

24 Sep 2026 15:15:04 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Publisher rating · CRITICAL